Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D19/00—Axial-flow pumps
  • F04D19/02—Multi-stage pumps
  • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
  • F04D19/046—Combinations of two or more different types of pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/16—Combinations of two or more pumps ; Producing two or more separate gas flows
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M3/00—Investigating fluid-tightness of structures
  • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
  • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
  • G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
  • G01M3/202—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material using mass spectrometer detection systems
  • G01M3/205—Accessories or associated equipment; Pump constructions

Definitions

• the invention relates to a device for mass spectrometric leak detection with a three-stage turbomolecular pump and booster pump.
• Mass spectrometric leak detection devices are known in which a mass spectrometer is evacuated by a multi-stage turbomolecular pump, the outlet of the turbomolecular pump being evacuated via a backing pump against atmospheric pressure. It is known from DE 10 2014 223 841 A1, for example, to evacuate the test object to be examined using a separate booster pump, the outlet of which is evacuated via the backing pump of the mass spectrometric turbomolecular pump. The backing pump generates the backing vacuum for both the mass spectrometric turbomolecular pump and the booster pump.
• the booster pump has two stages with an intermediate gas outlet which is arranged between the two pump stages and which is connected in a gas-conducting manner to an intermediate gas inlet of the multi-stage, eg three-stage, turbomolecular pump.
• a partial flow is branched off via the connection branch between the booster pump and the turbomolecular pump and fed to the mass spectrometer in countercurrent through the input stage of the turbomolecular pump.
• Test gas usually helium
• Test gas can accumulate at the outlet of the booster pump if the delivery capacity of the backing pump is not sufficient to discharge the test gas.
• the accumulated test gas at the outlet of the booster pump can get through the output pump stage of the booster pump and the connecting branch into the intermediate gas inlet of the turbomolecular pump of the mass spectrometer and from there through the input stage of the turbomolecular pump into the mass spectrometer, where the test gas generates a background signal in the form of an offset error.
• the invention is therefore based on the object of creating an improved device for mass spectrometric leak detection with a multi-stage booster pump and turbomolecular pump.
• the mass spectrometric turbomolecular pump which is arranged between the mass spectrometer and the backing pump, is designed as an at least three-stage vacuum pump, with a first intermediate gas inlet between the input pump stage and the middle pump stage and a second Intermediate gas inlet is formed between the middle pump stage and the output pump stage.
• the first intermediate gas inlet is connected via a first connection branch to an intermediate gas outlet between the two pump stages of the at least two-stage booster pump, while the outlet of the booster pump, i.e. the outlet of the output pump stage, is connected to the second intermediate gas inlet of the mass spectrometric turbomolecular pump via a second connection branch.
• the first connection branch and/or the second connection branch preferably each have a separately controllable valve for selectively closing the respective connection branch.
• the first connection branch and the second connection branch can be connected to one another in a gas-conducting manner by a bridge branch.
• the bridge arm also has a separately controllable valve for selectively closing the bridge arm.
• the inlet of the booster pump is provided with a connection for the test item.
• the inlet of the booster pump can be connected to the inlet of the backing pump and the outlet of the mass spectrometric turbomolecular pump via a bypass branch, the bypass branch also having a separately controllable valve for selectively closing the bypass branch.
• the test object can be evacuated directly and exclusively via the backing pump to the atmosphere via the bypass branch, without the booster pump or the turbomolecular pump evacuating the test object.
• FIG. 1 shows an embodiment of the device according to the invention.
• a mass spectrometer 12 is evacuated by a three-stage turbomolecular pump 14, the mass spectrometer 12 being connected in a gas-conducting manner to the inlet 16 of the input pump stage 18 of the turbomolecular pump.
• a backing pump 22 is connected in a gas-conducting manner to the outlet of the turbomolecular pump 14 .
• the outlet of the turbomolecular pump 14 is formed by the outlet 20 of the outlet pump stage 24 .
• a middle pump stage 26 is provided between the input pump stage 18 and the output pump stage 24 of the mass spectrometric turbomolecular pump 14 .
• the gas line path 28 connecting the outlet of the turbomolecular pump to the backing pump 22 is provided with a separately controllable valve 30 for selectively closing the gas line path 28 .
• the outlet 32 of the first pump stage 18 and the inlet 34 of the middle pump stage 26 are connected in a gas-conducting manner to a first intermediate gas inlet 36 of the turbomolecular pump 14 .
• the outlet 38 of the middle pump stage 26 and the inlet 40 of the outlet pump stage 24 are connected in a gas-conducting manner to a second intermediate gas inlet 42 .
• a two-stage booster pump 44 has an input booster pump stage 46 and an output booster pump stage 48, with the outlet 50 of the input booster pump stage 46 and the input 52 of the output booster pump stage 48 being connected in a gas-conducting manner to an intermediate gas outlet 54 of the booster pump 44.
• the output 56 of the output booster pump stage 48 forms the outlet of the booster pump 44.
• the input 58 of the input booster pump stage 46 forms the inlet of the booster pump 44 and is gas-conductively connected to a connection 60 for connecting the test object to be examined.
• the intermediate gas outlet 54 and the first intermediate gas inlet 36 are connected to one another in a gas-conducting manner by a first connecting branch 62 .
• the outlet 56 and the second intermediate gas inlet 42 are connected to one another in a gas-conducting manner by a second connection branch 64 .
• the first connection branch 62 has a separately controllable valve 66 for selectively closing the first connection branch 62 .
• the second connection branch 64 has a selectively controllable valve 68 for selectively closing the second connection branch 64 .
• the first connection branch 62 and the second connection branch 64 are connected to one another in a gas-conducting manner by a bridge branch 70 .
• the bridge arm 70 has a selectively controllable valve 72 for selectively closing the bridge arm 70 .
• the test specimen connection 60 and the inlet 58 of the booster pump 44 are connected in a gas-conducting manner via a bypass branch 74 to the inlet 76 of the backing pump 22 and to the outlet 20 of the mass-spectrometric turbomolecular pump 14 .
• the bypass branch 74 has a selectively controllable valve 78 for closing the bypass branch 74 separately.
• the gas line path 80 connecting the output 50 of the input booster pump stage 46 and the input 52 of the output booster pump stage 48 is provided with a flow restrictor 53 arranged in the area of the input 52 of the output booster pump stage 48 .
• the two pump stages 46, 48 of the booster pump 44 are arranged on a common shaft, the input booster pump stage 46 being a turbomolecular pump stage and the output booster pump stage 48 being a Holweck stage.
• the pump stages 18, 26, 24 of the mass spectrometric turbomolecular pump 14 can also be arranged on a common shaft.
• the input pump stage 18 and the middle pump stage 26 can be part of a two-stage turbomolecular pump, the two pump stages 18, 26 of which are arranged on a common rotor shaft and thereby form a common turbomolecular pump stage.
• the output pump stage 24 can be a Holweck stage.
• the output pump stage 24 can be arranged on the same shaft as the two turbomolecular pump stages 18, 26.
• the backing pump 22 is preferably designed separately from the mass spectrometric turbomolecular pump 14 and from the booster pump 44 and does not share any common rotor shafts with them. However, it is conceivable that the backing pump 22 on the same rotor shaft is arranged, such as one or more pumping stages of the turbomolecular pump 14 and/or the booster pump 44.
• the test specimen connected to the test specimen connection 60 is evacuated with the valve 78 in the bypass branch 74 open by the fore-vacuum pump 22 via the bypass branch 74 .
• the valve 30 in the gas line path 28 is also opened in order to evacuate the mass spectrometer 12 via the turbomolecular pump 14 and the fore-vacuum pump 22 . In this operating state, referred to as "large”, it is already possible to detect large leaks with the mass spectrometer 12 .
• the valve 78 in the bypass branch 74 is closed and the valves 66, 68 in the connecting branches 62, 64 are opened.
• part of the test gas e.g. helium or hydrogen

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Non-Positive Displacement Air Blowers (AREA)
• Examining Or Testing Airtightness (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=77998967

Family Applications (1)

Country Status (8)

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Citations (5)

Family Cites Families (11)

• 2020
  • 2020-12-10 DE DE102020132896.6A patent/DE102020132896A1/de active Pending
• 2021
  • 2021-09-21 JP JP2023535465A patent/JP7781884B2/ja active Active
  • 2021-09-21 EP EP21782676.7A patent/EP4259939B1/de active Active
  • 2021-09-21 WO PCT/EP2021/075897 patent/WO2022122206A1/de not_active Ceased
  • 2021-09-21 CN CN202180082542.6A patent/CN116601391B/zh active Active
  • 2021-09-21 US US18/266,251 patent/US20240044737A1/en active Pending
  • 2021-09-21 KR KR1020237020242A patent/KR20230124907A/ko active Pending
  • 2021-11-26 TW TW110144222A patent/TWI894400B/zh active

Patent Citations (5)

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