Friction vacuum pump with staged rotor and stator

摘要

The connection openings (36,37) lie in one plane end parallel to the rotor axis (15). The pump stages (12-14) lie to one side of the connections with stages (13,14) of larger diameter than the preceding stages (12,13) in which case the angle of the opening (36,37) plane is adapted to the increasing diameter in the direction of axis (15). The two openings form part of the general housing (2) and the first two stages (12,13) are turbo-molecular with rotors and stator designed to give high compression ratio in stage (11) and high vacuum in stage (13). Both stages (12,13) are spaced (a) by one third of the motor diameter. The diameter of connection (37) joined to gas inlet (38) amounts to twice the pump stage spacing specified (a).