Vacuum pump and mass spectrometer

Patent metadata

Field	Value
Publication number	US-9989069-B2
Application number	US-201615234358-A
Country	US
Kind code	B2
Filing date	Aug 11, 2016
Priority date	Sep 15, 2015
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

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.

First claim

What is claimed is:

1. A vacuum pump comprising:
a first pump stage;
a second pump stage
provided on a pump downstream side of the first pump stage, and
including 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.

2. The vacuum pump according to claim 1 , wherein
the gas path includes at least one of a groove formed at an outer peripheral surface of the cylindrical stator or a groove formed at an inner peripheral surface of a pump housing provided to cover an outer peripheral side of the cylindrical stator.

3. The vacuum pump according to claim 1 , wherein
the gas path is formed facing an entire opening area of the one or more through-holes.

4. A mass spectrometer comprising:
the vacuum pump according to claim 1 ;
a first analysis unit;
a second analysis unit configured to operate in a higher pressure region than that of the first analysis unit;
a first chamber in which the first analysis unit is housed and which is provided with a first exhaust port connected to the first suction port of the vacuum pump; and
a second chamber in which the second analysis unit is housed and which is provided with a second exhaust port connected to the second suction port of the vacuum pump.

Assignees

• Shimadzu Corp

Inventors

• Manabe Masashi

Classifications

• F04D29/545

  Ducts · CPC title

• F05B2240/12

  Fluid guiding means, e.g. vanes · CPC title

• F04D19/044 Primary

  Holweck-type pumps · CPC title

• F05B2260/2241

  using fins or ribs · CPC title

• H01J49/24

  Vacuum systems, e.g. maintaining desired pressures · CPC title