MOLECULAR VACUUM PUMP

摘要

The present invention relates to a molecular vacuum pump that includes a housing (1) comprising openings (5, 6) for communication with open air and with a chamber where vacuum must be created. The housing includes a rotor (7) which is mounted so as to define radial and axial gaps. The outer surface of the rotor (7) comprises helical grooves (8) extending practically on the entire length thereof, wherein said grooves define a flow section which comprises at least two pumping stages and is located between said openings (5, 6). These grooves (8) are made in the shape of a multi-start thread whose inner diameter increases starting from the suction side, where openings (5) communicate with the chamber in which vacuum must be generated, towards the discharge side where openings (6) communicate with the open air. The axial opening (9) of the rotor (7) includes a shaft (10) having its ends rigidly connected to the housing (1). The radial gap between the shaft (10) and the rotor (7) opening (9) is used as a gas-dynamics bearing for said rotor (7).