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
  • G01M3/205—Accessories or associated equipment; Pump constructions

Definitions

• the invention relates to a device and a method for sniffing leak detection with a sniffer probe.
• the sniffer probe is connected via a gas flow path to a vacuum pump which produces a reduced gas pressure relative to the environment of the sniffer probe.
• gas is sucked from the vicinity of the sniffer probe through a suction port on a sniffer tip of the sniffer probe and conveyed along the gas flow path to the vacuum pump.
• Gas sucked in by the sniffer probe is analyzed by means of a gas analyzer. This creates a conveying gas flow from the sniffer tip to the gas analyzer.
• the gas analyzer can inspect the intake gas flow stream for the presence of a test gas, with which the test object was previously filled.
• test object is filled with test gas in such a way that the gas pressure within the test object is greater than that outside the test object, so that test gas escapes through a possible leak in an outer wall of the test object. If now the sniffer probe is guided along the surface of the test object and thereby reaches the vicinity of the leak, the test gas emerging from the leak is sucked by the sniffer probe and detected by the gas analyzer.
• a flow of carrier gas When sniffing the leak, a flow of carrier gas must be kept constant in the sniffer line in order to convey test gas leaving the leak to the gas analyzer and to detect the test gas flow emerging from the leak in a defined manner and thus obtain a quantitative measure of the leakage rate.
• a special feature is that the concentration of the test gas decreases in the sucked with the sniffer probe conveying gas flow even at a constant flow of carrier gas when the distance between the sniffer probe and leak increases or increases the (transverse) sniffer speed. Conversely, the proportion of test gas in the aspirated gas stream increases with decreasing distance and lower relative speed between the sniffer probe and the leak. Measurements are therefore only comparable with the same "sniffing parameters": distance, transversal velocity, conveying gas flow If all sniffer parameters were known at all times, the measurement result would always be correct, regardless of distance, velocity and flow of conveying gas.
• the distance to the leak is a parameter that can make it difficult to find leaks at unknown locations, which is why a larger delivery gas flow would be desirable at large or unknown distances (eg to the hidden leaks).
• a small flow of carrier gas is advantageous in order to be able to measure even very small leakage rates.
• the invention is therefore based on the object to improve the detection of unknown leaks and the detection limit for test gas in the measurement of small leakage rates.
• the device according to the invention is defined by claim 1.
• the method according to the invention is defined by claim 7.
• a distance sensor is provided which is designed to measure the distance between the distance sensor and a test object along which the sniffer probe is guided.
• a controller is provided and configured to detect the measured distance and to vary the delivery gas flow along the gas flow path from the sniffer tip to the vacuum pump depending on the detected distance. In doing so, a larger gas flow should be set for a greater distance than for a smaller distance. As long as the distance does not change, the conveying gas flow is kept constant.
• the distance sensor may be a mechanical sensor with a spring element and / or a magnetic contact or mechanically operated electrical switch. When closing the contact or switch, a predetermined distance is considered recognized.
• the signal of the distance sensor is preferably transmitted by electronic means to the electronic control.
• the distance sensor may be an optical sensor or a act acoustic sensor (ultrasonic sensor).
• the sensor can be designed to emit and receive electromagnetic waves (for example radar).
• the senor can also be designed to detect the relative speed with respect to the surface of the test object, against which the sniffer probe is guided and moved.
• a separate speed sensor may be provided in addition to the distance sensor.
• the speed sensor should also be designed to transmit and receive electromagnetic waves (light, radio, sound). The calculation of the distance and / or the speed can be carried out by an electronic system, for example by the control electronics, in a known manner, for example using the Doppler principle.
• the controller may be configured to act on the vacuum pump and / or on a mechanically or electrically operable throttle arranged along the gas flow path.
• the controller can set and change their speed.
• the controller can set and change the flow resistance of the throttle.
• the gas analyzer can be designed to analyze the gas delivered by the conveying gas flow.
• the gas analyzer can be designed to analyze the gas drawn in by the sniffer probe and conveyed via a second gas flow path.
• the gas analyzer can be arranged along the relevant gas flow path. In the case of the second gas flow path, this can be connected to a second vacuum pump.
• the amount of gas delivered along the second gas flow path is related to the gas flow provided with the first gas flow path as a function of the distance.
• Figure 3 is a schematic representation of the third embodiment
• Figure 4 shows the relationship between distance, speed and
• the Schnüffellecksucher 10 has a sniffer probe 12, the sniffer tip 14 is provided with a suction port 16 for sucking a gas stream.
• the rear, the suction port 16 opposite end of the sniffer probe 12 is connected via a first gas flow path 18 with a first vacuum pump 20.
• the first vacuum pump 20 is designed to generate a reduced gas pressure with respect to the environment 22 of the sniffer probe 12.
• the vacuum pump 20 is designed as a gas feed pump and sucks gas from the environment 22 through the intake opening 16 and conveys it along the first gas flow path 18.
• the sniffer probe 12 is provided with a distance sensor 24 which is arranged on the sniffer tip 14 in the region of the intake opening 16.
• the distance sensor 24 is designed to detect the distance 26 relative to the surface 28 of a test object 30, in the vicinity of which the sniffer probe 12 is positioned in order to suck test gas 34 leaving a possible leak 32.
• Gas sucked in by the sniffer probe 12 through the suction opening 16 is supplied to a gas analyzer 36, which may, for example, be a mass spectrometer.
• the gas analyzer 36 is designed to detect test gas 34.
• the distance 26 measured by the distance sensor 24 is transmitted via an electronic line 38 to a controller 40.
• the controller 40 may be, for example, a microcontroller or a computer.
• the controller 40 is designed to change and adjust the gas flow conveyed along the first gas flow path 18 as a function of the measured distance 26. This can be done via an electrical line 42 in the following ways:
• the flow resistance of a controllable throttle 44 arranged along the first gas flow path 18 is adjusted or changed by the controller 40.
• the throttle 44 may be interposed between the sniffer probe 12 and the gas analyzer 36 and / or (shown in phantom in FIG. 1) between the gas analyzer 36 and the vacuum pump 20 ,
• the controller 40 via the line 42, the delivery rate of the pump 20 set or change, for example, in which the controller 40, the rotational speed of the pump 20 sets.
• the gas analyzer 36 is arranged along the first gas flow path 18.
• the gas analyzer 36 is arranged along a second gas flow path 46 different from the first gas flow path 18.
• the second gas flow path 46 connects the sniffer probe 12 to a second vacuum pump 48 different from the first vacuum pump 20. This is based on the idea that the flow set along the first gas flow path 18 via the controller 40 at least indirectly also conveys the flow along the second gas flow path 46 Flow or the amount of gas conveyed along the second gas flow path 46 influenced.
• the controller 40 can adjust or change the flow resistance via a throttle corresponding to the throttle 44 of the first exemplary embodiment.
• the first gas flow path 18 may include a valve 50, which is arranged adjacent to the throttle 44 in FIGS. 2 and 3 and, like the throttle 44, can be actuated by the controller 40 via the line 42. With the valve 50 closed, no gas is delivered along the first gas flow path 18, so that all the gas drawn in by the sniffer probe is supplied to the gas analyzer 36 via the second gas flow path 46. With the valve 50 open, only a portion of the gas aspirated by the sniffer probe 12 passes via the second gas flow path 46 to the gas analyzer 36, while another portion of the aspirated gas is directed along the first gas flow path 18.
• the controller 40 similarly as in the first embodiment, also act directly on the delivery rate of the first vacuum pump 20 and turn it on or off, for example.
• the entire of the Sniffer probe 12 sucked gas flow along the second gas flow path 46 is supplied to the gas analyzer 36.
• the pump 20 is turned on, a part of the sucked gas is conveyed via the first gas flow path 18, similarly to the valve 50 being opened, while another part is supplied to the gas analyzer 36 via the second gas flow path 46.
• the third embodiment differs from the second embodiment by a separate from the distance sensor 24, also arranged on the sniffer tip 14 speed sensor 52, which is designed to measure the relative speed 54 of the sniffer tip 14 relative to the surface 28.
• the measured speed is also supplied to the controller 40 via a line, not shown in FIG.
• the controller 40 is configured to adjust or change the gas flow guided along the first gas flow path 18 in the manners described above.
• FIG. 4 shows the relationship between the distance 26, the relative velocity 54 and the flow 56 to be adjusted along the first gas flow path 18. The larger the distance 26 and / or the greater the velocity 54, the lower the flow 56 is to be set to equal To detect quantity of test gas 34 and to leave the detection limit of the test gas to detect a leak 32 unchanged.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Examining Or Testing Airtightness (AREA)
• Measuring Volume Flow (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (3)

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• 2016
  • 2016-10-06 DE DE102016219401.1A patent/DE102016219401A1/de not_active Withdrawn
• 2017
  • 2017-09-28 JP JP2019518400A patent/JP6887493B2/ja active Active
  • 2017-09-28 WO PCT/EP2017/074680 patent/WO2018065298A1/de not_active Ceased
  • 2017-09-28 CN CN201780052944.5A patent/CN109716089B/zh active Active
  • 2017-09-28 EP EP17781048.8A patent/EP3523617B1/de active Active
  • 2017-09-28 US US16/330,902 patent/US11022515B2/en active Active
  • 2017-10-06 TW TW106134600A patent/TWI743225B/zh active

Patent Citations (3)

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