Classifications

• • 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
• • 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 method for detecting light gas components in the external environment of a mass spectrometric countercurrent leak detector.
• Mass spectrometric countercurrent leak detection devices typically have: a connection to a test object to be tested or to a test chamber into which the test object to be tested is placed, a gas detector connected to the connection in the form of a mass spectrometer, a high vacuum pump, usually in the form of a turbomolecular pump, their Inlet with the mass spectrometer, the outlet of which is connected to the inlet of a backing pump, the outlet of which conveys the evacuated gas into the surrounding atmosphere.
• the high vacuum pump typically also has an intermediate gas inlet, which is connected to the test object connection or the Test chamber connection is connected.
• the fore-vacuum pump can also be connected directly to the mass spectrometer via a bypass line that bridges the high-vacuum pump for massive leak detection.
• the test object connection or test chamber connection can be connected to the inlet of the backing vacuum pump via an additional booster pump, whereby the booster pump can be connected to the intermediate gas inlet of the high vacuum pump.
• the test chamber connection and the test chamber connected to it are first evacuated using the backing pump and the booster pump, if present.
• the backing pump also generates the required backing vacuum at the outlet of the high vacuum pump so that the high vacuum pump evacuates the mass spectrometer.
• a connecting valve in the connection between the test chamber connection and the high vacuum pump is opened, whereby gas flows from the test chamber into the high vacuum pump and flows in countercurrent through the high vacuum pump into the mass spectrometer and there is analyzed.
• gas from the inside of the test object enters the test chamber and from there in countercurrent into the mass spectrometer and can be detected there.
• Light gas components are gas components of the air mixture from the ambient air that are lighter than air.
• a light gas component can be, for example, helium.
• the ambient helium concentration is determined using separate gas analyzers.
• a mass spectrometric countercurrent leak detector it is possible to switch off the backing pump and turn it on Open the gas ballast valve of the fore-vacuum pump in order to ventilate it and thereby brake it.
• gas can be introduced into the mass spectrometer via the gas ballast valve and a bypass line bridging the high-vacuum pump for massive leak detection and measured there.
• the bypass line is a direct connecting line between the inlet of the backing pump and the mass spectrometer.
• such bypass lines are provided with an additional throttle for massive leak detection.
• the invention is based on the object of creating an improved method for determining the concentration of a light gas component in the environment of a mass spectrometric countercurrent leak detector.
• Claim 1 is based on a mass spectrometric countercurrent leak detection device with a backing vacuum pump, a high vacuum pump and a mass spectrometric gas detector.
• the outlet of the fore-vacuum pump can be open to the atmosphere or, for example, connected to an exhaust line that discharges the pumped gases to the atmosphere.
• the input of the backing pump is connected to an output of the high vacuum pump.
• the inlet of the high vacuum pump is connected to the mass spectrometer.
• An intermediate gas inlet of the high vacuum pump is connected via a separate connecting line to a connection for a vacuum test chamber and/or a test specimen.
• the connection for the test chamber or the test specimen could be connected to the inlet of the backing vacuum pump via an additional booster pump - but this is not absolutely necessary.
• an intermediate gas outlet of the booster pump is connected to the intermediate gas inlet of the high vacuum pump.
• the high vacuum pump is typically a turbomolecular pump.
• the backing pump is equipped with a gas ballast that is open to the outside atmosphere or flows into a fresh air line.
• the gas ballast can have a selectively switchable valve and can therefore be either opened or closed.
• the gas ballast valve can be opened or air from the external environment of the fore-vacuum pump can be admitted into the fore-vacuum pump through the open gas ballast in such a way that at least one light Gas component, such as helium, flows out in countercurrent through the fore-vacuum pump through its inlet and from there enters the mass spectrometer, while the remaining gas components are fed to the environment through the outlet of the fore-vacuum pump.
• an air inlet can open directly into the fore-vacuum area of the fore-vacuum pump, that is, for example, into the connecting line between the fore-vacuum pump and the high-vacuum pump and/or into the bypass line described below for bridging the high-vacuum pump.
• the invention therefore offers the advantage that the analysis of the ambient air and in particular the measurement of concentrations of light gas components of the ambient air can be carried out during the actual leak detection with the mass spectrometer without having to interrupt the leak detection and/or having to switch off the backing pump.
• the light gas component to be measured can be introduced in countercurrent from the inlet of the fore-vacuum pump to the outlet of the high-vacuum pump, through the high-vacuum pump to its inlet and from there into the mass spectrometer.
• the light gas component to be measured can enter the mass spectrometer through a bypass line connecting the inlet of the fore-vacuum pump to the mass spectrometer for massive leak detection, which bridges the high-vacuum pump.
• the bypass line can be provided with an additional throttle. Such a bypass line makes it possible to detect particularly large leaks before the high vacuum pump in the mass spectrometer has generated the required high vacuum pressure.
• the light gas component then flows counter to the pumping direction from the gas ballast through the backing pump towards the mass spectrometric gas detector.
• the pressure at the outlet of the high vacuum pump only depends on the speed of the backing pump and not on the proportion of the light gas component to be measured (e.g. helium) in the ambient air.
• the measured stroke in the leak rate signal or raw ion current signal of the mass spectrometer depends on the helium ambient concentration or on the concentration of the light gas component in the ambient air.
• Light gases such as helium
• the lower the speed of the backing pump the more helium flows through the backing pump in countercurrent through its inlet back into the mass spectrometer.
• the increase in the light gas component is greater than the total pressure increase in Mass spectrometer due to the different compressions.
• the determination of the ambient concentration of the light gas component can be carried out during the actual leak detection or after a leak detection of a test object, without having to switch off the pumps.
• the backing pump and the high vacuum pump continue to run, so that there is no time for shutting down and then restarting the vacuum pumps.
• Fig. 1 shows a first exemplary embodiment
• Fig. 2 shows a second exemplary embodiment.
• the gas detector 12 is connected in a gas-conducting manner to the input 14 of a high vacuum pump 16 in the form of a turbomolecular pump.
• the output 18 of the high vacuum pump 16 is connected in a gas-conducting manner to the input 22 of a backing pump 24 via a connecting line provided with a selectively controllable valve 20.
• the outlet 26 of the backing pump 24 is open to the atmosphere or opens into an exhaust pipe.
• the input 22 of the backing pump 24 is also connected to the mass spectrometer 12 via a separate bypass line 28.
• the bypass line 28 bridges the high vacuum pump 16 and the controllable valve 20 and is provided with a throttle 30 to enable massive leak detection.
• the leak detection device 10 is also provided with a connection 32 for a test chamber or a test specimen.
• a test chamber 35 is connected to the connection 32 using vacuum technology.
• the test chamber 35 accommodates a test item to be tested for leaks and is then evacuated.
• the connection 32 is connected to a booster pump 34 in a gas-conducting manner.
• the input 36 of the booster pump is connected to the connection 32 in a gas-conducting manner, while the output 38 of the booster pump is connected to the input 22 of the backing pump via a further gas line 42 provided with a further valve 40.
• Fig. 2 shows an embodiment without a booster pump.
• the exemplary embodiment of FIG. 2 corresponds to that of FIG. 1 except for the missing booster pump 34 and the air inlet 53.
• An intermediate gas line 46 having a further selectively actuable valve 44 connects an intermediate gas outlet 48 of the booster pump 34 with an intermediate gas inlet 50 of the high vacuum pump 16.
• the fore-vacuum pump 24 is further provided with a gas ballast valve 52 which is designed separately from the inlet 22 and the output 26 and which connects the interior of the fore-vacuum pump 24 with the external environment 54 of the fore-vacuum pump 24 and the leak detection device 10.
• the gas ballast valve 52 is selectively operable and can be opened and closed.
• a throttle point 51 is provided between the gas ballast valve 52 and the fore-vacuum pump 24, which flows through the gas ballast into the Backing vacuum pump 24 determined gas flow.
• the gas ballast valve 52 can be omitted.
• only the throttle point 51 is provided at the inlet forming the gas ballast of the fore-vacuum pump 24.
• the throttle point 51 can be made possible, for example, by selecting a suitable cross section of the gas ballast inlet.
• an air inlet 53 is provided as an exemplary embodiment, which can be open to the atmosphere or connected to a fresh air line, and which opens into the connecting line between the inlet 22 and the valve 20, that is to say into the backing vacuum pump 24 with the high vacuum pump 16 connecting connecting line.
• the air inlet 35 is shown in FIG. 2 in addition to the air inlet via the gas ballast of the backing vacuum pump 24, but can also be provided as an alternative without the gas ballast. In this case, the gas ballast on the fore-vacuum pump 24 is eliminated.
• the air inlet 53 is also provided with a throttle similar to the throttle point 51 of the gas ballast. The same is also possible in the exemplary embodiment in FIG.
• the test chamber 35 is evacuated using the backing pump 24 and the booster pump 34.
• the backing pump 24 generates the backing vacuum required at the outlet of the high vacuum pump 16, into which the high vacuum pump 16 evacuates the contents of the mass spectrometer 12. Meanwhile, the backing pump 24 also evacuates the mass spectrometer 12 directly via the bypass line 28.
• the valve 44 is opened and the valve 40 is closed so that test gas and / or leakage gas from the interior of the Test chamber 35 passes through the booster pump 34, the intermediate gas line 36 and in countercurrent through the high vacuum pump 16 into the mass spectrometer 12 and can be analyzed there.
• the gas ballast valve 52 is opened while the backing pump 24 is still running.
• the gas ballast 52 is permanently open and, if necessary, connected to a fresh air line.
• the gas ballast 52 can be open to the atmosphere.
• the speed of the vacuum pump is modulated or at least changed between two different operating states, for example changed between the final speed of the backing pump 24 and a reduced speed.
• the changed pump speed results in a change in the helium partial pressure and the total pressure at the inlet 22 of the fore-vacuum pump 24.
• a change or a signal swing can then be measured for the helium component because the helium comes out of the fore-vacuum pump 24 either via the bypass 28 or in Countercurrent passes through the high vacuum pump 16 into the mass spectrometer 12.
• a gas ballast valve 52 the supply of air flowing from the environment 54 into the backing vacuum pump 24 can be influenced by opening and closing the gas ballast valve 52.
• an air inlet for supplying ambient air directly into the fore-vacuum region of the fore-vacuum pump 24 can be provided, for example as an air inlet 53 in the connecting line between the fore-vacuum pump 24 and high vacuum pump 16, between the inlet 22 and the valve 20 and /or into the bypass line 28.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Examining Or Testing Airtightness (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=86657751

Family Applications (1)

Country Status (6)

Family Cites Families (5)

• 2022
  • 2022-06-22 DE DE102022115562.5A patent/DE102022115562A1/de active Pending
• 2023
  • 2023-05-25 WO PCT/EP2023/064001 patent/WO2023247132A1/de not_active Ceased
  • 2023-05-25 JP JP2024573578A patent/JP2025519694A/ja active Pending
  • 2023-05-25 CN CN202380042061.1A patent/CN119256215A/zh active Pending
  • 2023-05-25 EP EP23728063.1A patent/EP4544280A1/de active Pending
  • 2023-06-21 TW TW112123447A patent/TW202413911A/zh unknown

Also Published As

Similar Documents

Legal Events