VACUUM PUMP AND MASS SPECTROMETER

摘要

One or more through-holes communicating with one or more of the plurality of screw grooves are formed at the cylindrical stator, a total of circumferential dimensions of the one or more through-holes formed at the cylindrical stator is set at equal to or greater than a circumferential dimension of an outer peripheral surface region of the cylindrical stator facing the second suction port, and a gas path through which inflow gas through the second suction port is guided to a screw groove is provided, the one or more through-holes penetrating through the screw groove and the screw groove being apart from the region facing the second suction port.

主权项

1. A vacuum pump comprising:
a first pump stage; a second pump stage
provided on a pump downstream side of the first pump stage, andincluding a cylindrical stator configured such that a plurality of screw grooves and a plurality of screw threads are alternately formed in an inner peripheral surface circumferential direction, and a cylindrical rotor provided on an inner peripheral side of the cylindrical stator; a first suction port provided on an upstream side of the first pump stage; and a second suction port provided on an downstream side of the first pump stage and communicating with the second pump stage, wherein one or more through-holes communicating with one or more of the plurality of screw grooves are formed at the cylindrical stator, a total of circumferential dimensions of the one or more through-holes formed at the cylindrical stator is set at equal to or greater than a circumferential dimension of an outer peripheral surface region of the cylindrical stator facing the second suction port, and a gas path through which inflow gas through the second suction port is guided to a screw groove is provided, the one or more through-holes penetrating through the screw groove and the screw groove being apart from the region facing the second suction port.