Multiple port vacuum pump system

Patent metadata

Field	Value
Publication number	US-10422338-B2
Application number	US-201414459174-A
Country	US
Kind code	B2
Filing date	Aug 13, 2014
Priority date	Aug 20, 2013
Publication date	Sep 24, 2019
Grant date	Sep 24, 2019

Abstract

A vacuum pump system for evacuating at least five volumes comprising a turbomolecular pump and a forevacuum pump arranged to pump an output of the turbomolecular pump arrangement to atmosphere. The turbomolecular pump has at least five pumping stages separated by rotor blades. Not more than three pumping stages have pumping speeds in excess of ⅓ of the highest pumping speed when under vacuum and/or a pumping port cross section in excess of ⅓ of the highest pumping port cross section, and at least two pumping stages have pumping speeds less than ¼ of the highest pumping speed when under vacuum and/or a pumping port cross section of less than ¼ of the biggest pumping port cross section. The ratio of pressures between the pumping stage with the highest pressure and the pumping stage with the lowest pressure is at least 100000:1 when under vacuum.

First claim

The invention claimed is:

1. A mass spectrometer system comprising:
an ion source, a mass analyzer and an optical arrangement for transporting ions from the ion source to the mass analyzer, wherein the mass spectrometer system comprises at least five volumes pumped by a vacuum pump system comprising,
a forevacuum pump and a turbomolecular pump arrangement, the at least five volumes including a volume at a lowest pressure containing a mass analyzer and volumes containing components of the ion optical arrangement which are held at successively lower pressures from a volume adjacent the ion source to the volume containing the mass analyzer, the system arranged so that the forevacuum pump pumps an output of the turbomolecular pump arrangement to atmosphere;
the turbomolecular pump arrangement including multiple pumping ports corresponding to different pumping stages and is configured such that:
there are at least five pumping stages, each coupled to a respective one of the volumes of the mass spectrometer system;
each pumping stage is separated by at least one set of rotor blades;
not more than three pumping stages have (i) pumping speeds in excess of ⅓ of a highest pumping speed of a pumping stage when under vacuum or (ii) a pumping port cross section in excess of ⅓ of a biggest pumping port cross section;
at least two pumping stages have (iii) pumping speeds less than ¼ of the highest pumping speed of a pumping stage when under vacuum or (iv) a pumping port cross section of less than ¼ of the biggest pumping port cross section;
wherein a ratio of pressures between a pumping stage with the highest pressure and a pumping stage with the lowest pressure is at least 100000:1 when under vacuum.

2. The mass spectrometer system of claim 1 , wherein at least one pumping stage of the turbomolecular pump arrangement includes a molecular drag pump.

3. The mass spectrometer system of claim 1 , wherein:
not more than three pumping stages have pumping speeds in excess of 50 Ls −1 when under vacuum;
at least two pumping stages have pumping speeds less than 30 Ls −1 when under vacuum; and
wherein the forevacuum pump when in use maintains the output of the turbomolecular pump arrangement at a pressure of at least 1 mbar.

4. The mass spectrometer system of claim 1 , wherein when in use at working gas loads the ratio of pressures between any two adjacent pumping stages of the turbomolecular pump arrangement is between 10 and 1000.

5. The mass spectrometer system of claim 1 , wherein the greatest distance between any two pumping stages of the molecular pump arrangement is less than 400 mm.

6. The mass spectrometer system of claim 1 , wherein the volume at the lowest pressure is maintained below 1×10 −9 mbar.

7. The mass spectrometer system of claim 1 , wherein the pumping stage connected to the volume at the lowest pressure has the highest pumping speed when under vacuum or the biggest pumping port cross section.

8. The mass spectrometer system of claim 1 , wherein at least the volume at the lowest pressure is equipped with a heating arrangement for heating the volume.

9. The mass spectrometer system of claim 1 , wherein at least one pumping port surrounds a second pumping port such that the second pumping port seals against pressure within the first pumping port and not against atmosphere, or wherein at least the volume of a first pumping stage surrounds the volume of a second pumping stage such that the volume of the second pumping stage seals against pressure within the first pumping stage and not against atmosphere.

10. A mass spectrometer system comprising:
at least six volumes;
an atmospheric pressure ion source;
a mass analyzer;
an ion optical arrangement for transporting ions from the atmospheric pressure ion source to the mass analyzer;
a vacuum pump system including a forevacuum pump and a turbomolecular pump arrangement, the vacuum pump system arranged so that the forevacuum pump pumps an output of the turbomolecular pump arrangement to atmosphere;
the turbomolecular pump arrangement including multiple pumping ports corresponding to different pumping stages and is configured such that:
there are at least five pumping stages, each coupled to a volume;

each pumping stage is separated by at least one set of rotor blades;
not more than three pumping stages have (i) pumping speeds in excess of ⅓ of a highest pumping speed of a pumping stage when under vacuum or (ii) a pumping port cross section in excess of ⅓ of a biggest pumping port cross section;
at least two pumping stages have (iii) pumping speeds less than ¼ of the highest pumping speed of a pumping stage when under vacuum or (iv) a pumping port cross section of less than ¼ of the biggest pumping port cross section;
wherein a ratio of pressures between a pumping stage with the highest pressure and a pumping stage with the lowest pressure is at least 100000:1 when under vacuum; and,
wherein the forevacuum pump pumps a first volume adjacent the atmospheric pressure ion source, the first volume containing a first stage of the ion optical arrangement; and the turbomolecular pump arrangement pumps further volumes each containing further stages of the ion optical arrangement and/or the mass analyzer.

11. The mass spectrometer system of claim 10 , wherein the volume with the lowest pressure when under vacuum contains the mass analyzer.

12. The mass spectrometer system of claim 10 , wherein the ion optical arrangement comprises at least one from the group consisting of a mass filter, an ion trap and a collision cell.

13. The mass spectrometer system of claim 10 , wherein at least one first volume pumped by a pumping stage of the turbomolecular pump arrangement surrounds the volume with the lowest pressure when under vacuum, such that the volume at the lowest pressure seals against pressure within the first volume and not against atmosphere.

14. A method of evacuating at least five volumes comprising pumping an output of a turbomolecular pump arrangement to atmosphere with a forevacuum pump; and
pumping each volume via a respective one of at least five pumping stages of the turbomolecular pump arrangement; wherein each pumping stage is separated by at least one set of rotor blades;
not more than three pumping stages have pumping speeds in excess of ⅓ of the highest pumping speed when under vacuum;
at least two pumping stages have pumping speeds less than ¼ of the highest pumping speed when under vacuum;
wherein the ratio of pressures between the pumping stage with the highest pressure and the pumping stage with the lowest pressure is maintained at least at 100000:1 when pumping at working gas loads.

15. The method of claim 14 , wherein the at least 5 volumes comprise chambers connected by apertures and/or elongated flow restrictors, which chambers house ion optical components of a mass spectrometer.

Assignees

• Thermo Fisher Scient Bremen Gmbh

Inventors

• Makarov Alexander
• Balschun Wilko

Classifications

• F04D19/046 Primary

  Combinations of two or more different types of pumps · CPC title

• F04D19/042 Primary

  Turbomolecular vacuum pumps · CPC title

• Y10T137/86083

  Vacuum pump · CPC title

• H01J49/24

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