CN116858448A - High-sensitivity leakage detection device and method based on low-vacuum accumulation method - Google Patents
High-sensitivity leakage detection device and method based on low-vacuum accumulation method Download PDFInfo
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- CN116858448A CN116858448A CN202310636131.8A CN202310636131A CN116858448A CN 116858448 A CN116858448 A CN 116858448A CN 202310636131 A CN202310636131 A CN 202310636131A CN 116858448 A CN116858448 A CN 116858448A
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- 238000009825 accumulation Methods 0.000 title claims abstract description 146
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- 238000001819 mass spectrum Methods 0.000 claims abstract description 13
- 238000004949 mass spectrometry Methods 0.000 claims abstract description 9
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- 239000007789 gas Substances 0.000 description 98
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- 230000008569 process Effects 0.000 description 6
- 239000001307 helium Substances 0.000 description 5
- 229910052734 helium Inorganic materials 0.000 description 5
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 5
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- 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
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Abstract
The application relates to the technical field of vacuum leakage detection, in particular to a high-sensitivity leakage detection device and method based on a low vacuum accumulation method, wherein the device comprises a low vacuum accumulation leakage detection assembly, a leakage gas sampling assembly, a leakage gas mass spectrometry assembly and an evacuating unit, wherein: the low vacuum accumulation leak detection assembly is connected with the evacuating unit through an electromagnetic valve and an electric valve; the leakage gas sampling assembly is used for leading out low-vacuum gas and is arranged between the low-vacuum accumulation leakage detection assembly and the leakage gas mass spectrum analysis assembly; the leakage gas mass spectrometry component is connected with the evacuating unit through an electric valve; the evacuator is used for exhausting the leakage gas and providing vacuum conditions. The application combines low vacuum accumulation, current-limiting small hole sampling, selective air suction and partial pressure measurement, obviously shortens the leak detection time while detecting leak with high sensitivity, and solves the defect that the higher the leak detection sensitivity is, the longer the leak detection time is required in the traditional leak detection method.
Description
Technical Field
The application relates to the technical field of vacuum leakage detection, in particular to a high-sensitivity leakage detection device and method based on a low vacuum accumulation method.
Background
The helium mass spectrum leakage detection technology is the most widely applied in the technical field of vacuum leakage detection, has the advantages of high leakage detection sensitivity, quick instrument response, simple and convenient operation, safety, high efficiency, low cost, wide application and the like, and is widely applied in various fields of aerospace, aviation, energy sources, medicine and the like.
The traditional mass spectrum helium leakage detection is mainly realized by adopting a helium mass spectrum leak detector, and the He leakage rate measurement of the detected piece is mainly realized based on a dynamic comparison method, and when the leak detection sensitivity requirement is higher, the vacuum condition of the detected piece is required to be better.
For the detected piece with simple structure and small vacuum cavity volume, the vacuum condition acquisition can be realized in a short time by adopting an internal evacuation unit or an auxiliary unit of the helium mass spectrometer leak detector, and for the detected piece with complex or large vacuum cavity volume, the expected vacuum condition cannot be generated, or the required vacuum condition can be obtained only in a long time, so that the time cost is very high, and the leak detection requirement of batch industrial production cannot be met. Along with the actual demand of leak detection in mass industrialized production, which is higher and higher in the fields of aerospace, aviation, semiconductor, nuclear industry and the like, the allowable leak detection time is shorter and shorter, the existing helium mass spectrometer leak detection method cannot meet the demand.
Disclosure of Invention
The application provides a high-sensitivity leak detection device and method based on a low-vacuum accumulation method, which adopt a low-vacuum accumulation and current-limiting small hole sampling technology to realize accumulation and sampling of leakage gas He under the low-vacuum condition.
In order to achieve the above object, the present application provides a high sensitivity leak detection device based on a low vacuum accumulation method, comprising a low vacuum accumulation leak detection assembly, a leakage gas sampling assembly, a leakage gas mass spectrometry assembly and an evacuating unit, wherein: the low vacuum accumulation leak detection assembly is used for being connected with a to-be-detected piece to realize accumulation of leakage gas and is connected with the evacuating unit through an electromagnetic valve and an electric valve; the leakage gas sampling assembly is used for leading out low-vacuum gas, is arranged between the low-vacuum accumulation leakage detection assembly and the leakage gas mass spectrum analysis assembly, and is respectively connected with the low-vacuum accumulation leakage detection assembly and the leakage gas mass spectrum analysis assembly through an electric valve; the leakage gas mass spectrum analysis component is used for measuring the rising rate of the partial pressure of leakage gas and is connected with the evacuating unit through an electric valve; the evacuator is used for exhausting the leakage gas and providing vacuum conditions.
Further, the evacuation unit comprises a front-stage mechanical pump and a turbomolecular pump, and a first electromagnetic valve is arranged between the front-stage mechanical pump and the turbomolecular pump.
Further, the low vacuum accumulation leak detection assembly comprises a leak detection interface, a low vacuum accumulation chamber, a calibration leak and a low vacuum gauge, wherein: the leak detection interface is connected with the low vacuum accumulation chamber through a second electromagnetic valve; the calibration leak hole is connected with the low vacuum accumulation chamber through a third electromagnetic valve; the low vacuum gauge is directly connected with the low vacuum accumulation chamber; the low vacuum accumulation chamber is connected with a pre-stage mechanical pump through a fourth electromagnetic valve and is connected with a turbomolecular pump through a first electric valve.
Further, the leakage gas mass spectrometry assembly comprises a leakage detection chamber, an adsorption pump, a partial pressure mass spectrometer and a high vacuum gauge, wherein: the adsorption pump, the partial pressure mass spectrometer and the high vacuum gauge are directly connected with the leak detection chamber; the leak detection chamber is connected with a turbomolecular pump through a second electric valve.
Further, the leakage gas sampling assembly includes a first flow restricting orifice and a second flow restricting orifice, wherein: one end of the first current-limiting small hole is connected with the low vacuum accumulation chamber through a third electric valve, and the other end of the first current-limiting small hole is connected with the leak detection chamber through a fourth electric valve; one end of the second flow limiting small hole is connected with the low vacuum accumulation chamber through a fifth electric valve, and the other end of the second flow limiting small hole is connected with the leakage detection chamber through a sixth electric valve.
Further, the seventh electric valve is arranged at the two ends of the first current limiting small hole in parallel, and the eighth electric valve is arranged at the two ends of the second current limiting small hole in parallel.
Further, the nominal leak rate of the standard leak hole is less than or equal to 5 multiplied by 10 -10 Pa·m 3 /s。
Further, the first flow restricting orifice has a conductance of the order of 1×10 -5 m 3 And/s, the second flow-limiting orifice has a conductance level of 5×10 -7 m 3 /s。
Further, the partial pressure mass spectrometer is a quadrupole mass spectrometer, and the mass number range is less than or equal to 100amu.
In addition, the application also provides a method for applying the high-sensitivity leak detection device based on the low vacuum accumulation method, which comprises the following steps: step 1: starting a pre-stage mechanical pump, a first electromagnetic valve, a turbomolecular pump, a second electric valve, a high vacuum gauge, a seventh electric valve, a fourth electric valve, a sixth electric valve and an eighth electric valve in sequence, wherein when the high vacuum gauge displays that the pressure of a leak detection chamber is less than 1 multiplied by 10 -3 Starting a partial pressure mass spectrometer when Pa; step 2: installing a to-be-detected piece on a leak detection interface, starting a low vacuum gauge, closing a first electromagnetic valve, opening a fourth electromagnetic valve and a third electromagnetic valve, pre-evacuating a low vacuum accumulation chamber, the to-be-detected piece and a calibration leak hole, closing the fourth electromagnetic valve and a second electric valve after the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 10Pa, and vacuumizing the low vacuum accumulation chamber by using a turbo molecular pump; step 3: when the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 0.1Pa, closing the first electric valve, accumulating the leakage gas of the calibrated leak, wherein the accumulation time is 5-30 min, simultaneously opening the second electric valve, continuously evacuating the leak detection chamber by using the turbo molecular pump, closing the second electric valve after the accumulation of the leakage gas of the calibrated leak is finished, and observing the pressure indication of the low vacuum gauge; step 4: when the pressure displayed by the low vacuum gauge is more than or equal to 2Pa, opening a third electric valve, closing a seventh electric valve and a sixth electric valve, measuring the rising rate of the partial pressure of leakage gas He in the leakage detection chamber by using a partial pressure mass spectrometer, wherein the measuring time is between 20s and 1min, closing the third electric valve after the measuring is finished, and opening the seventh electric valveAn electric valve and a sixth electric valve; step 5: when the pressure displayed by the low vacuum gauge is less than 2Pa, opening a fifth electric valve, closing an eighth electric valve and a fourth electric valve, measuring the rising rate of the partial pressure of the leakage gas He in the leakage detection chamber by using a partial pressure mass spectrometer, wherein the measuring time is between 20s and 1min, closing the fifth electric valve after the measuring is finished, and opening the eighth electric valve and the fourth electric valve; step 6: closing a third electromagnetic valve, opening a second electric valve and a first electric valve, evacuating the low vacuum accumulation chamber and the leak detection chamber by using a turbo molecular pump, and repeating the steps 3-5 to accumulate background leakage gas after the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 0.1 Pa; step 7: after the background leakage gas is accumulated, closing a third electromagnetic valve, opening a second electric valve and a first electric valve, and evacuating a low vacuum accumulation chamber and a leakage detection chamber by using a turbomolecular pump; step 8: when the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 0.1Pa, coating the to-be-detected part by adopting a flexible cover box, filling leakage gas He into the flexible cover box, and repeating the steps 3-5 to accumulate the leakage gas after filling the He into the to-be-detected part; step 9: and according to the leakage gas accumulation of the calibrated holes, the background leakage gas accumulation and the rising rate of the He partial pressure of the leakage gas of the leakage detecting chamber obtained in the leakage gas accumulation process after the part to be detected is filled with He, the conductance value of the first current limiting small hole or the second current limiting small hole is used for calibrating the calibrated value of the holes, and the leakage value of the part to be detected is obtained by automatic calculation.
The high-sensitivity leak detection device and method based on the low vacuum accumulation method provided by the application have the following beneficial effects:
the application combines low vacuum accumulation, current-limiting small hole sampling, selective air suction and partial pressure measurement, shortens the leak detection time obviously while detecting leak with high sensitivity, solves the defect that the leak detection time is required to be longer as the leak detection sensitivity is higher in the traditional leak detection method, can realize the high-sensitivity leak detection requirement of a sealing device, can improve the leak detection working efficiency obviously, and meets the leak detection requirement of the fields of aerospace, aviation, semiconductor, nuclear industry and the like on the batch industrial production with higher and higher leak detection sensitivity and shorter leak detection time.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application, are incorporated in and constitute a part of this specification. The drawings and their description are illustrative of the application and are not to be construed as unduly limiting the application. In the drawings:
fig. 1 is a schematic diagram of a high sensitivity leak detection apparatus based on a low vacuum accumulation method according to an embodiment of the application;
in the figure: the device comprises a 1-leak detection interface, a 2-second electromagnetic valve, a 3-seventh electric valve, a 4-partial pressure mass spectrometer, a 5-high vacuum meter, a 6-third electric valve, a 7-first flow limiting small hole, an 8-fourth electric valve, a 9-low vacuum meter, a 10-low vacuum accumulation chamber, a 11-fifth electric valve, a 12-second flow limiting small hole, a 13-sixth electric valve, a 14-leak detection chamber, a 15-adsorption pump, a 16-fourth electromagnetic valve, a 17-eighth electric valve, a 18-second electric valve, a 19-third electromagnetic valve, a 20-first electric valve, a 21-calibrated leak hole, a 22-preceding mechanical pump, a 23-first electromagnetic valve and a 24-turbomolecular pump.
Detailed Description
In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe the embodiments of the application herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In the present application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate an azimuth or a positional relationship based on that shown in the drawings. These terms are only used to better describe the present application and its embodiments and are not intended to limit the scope of the indicated devices, elements or components to the particular orientations or to configure and operate in the particular orientations.
Also, some of the terms described above may be used to indicate other meanings in addition to orientation or positional relationships, for example, the term "upper" may also be used to indicate some sort of attachment or connection in some cases. The specific meaning of these terms in the present application will be understood by those of ordinary skill in the art according to the specific circumstances.
In addition, the term "plurality" shall mean two as well as more than two.
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
As shown in fig. 1, the application provides a high-sensitivity leak detection device based on a low vacuum accumulation method, which comprises a low vacuum accumulation leak detection assembly, a leakage gas sampling assembly, a leakage gas mass spectrometry assembly and an evacuating unit, wherein: the low vacuum accumulation leak detection assembly is used for being connected with a to-be-detected piece to realize accumulation of leakage gas and is connected with the evacuating unit through an electromagnetic valve and an electric valve; the leakage gas sampling assembly is used for leading out low-vacuum gas, is arranged between the low-vacuum accumulation leakage detection assembly and the leakage gas mass spectrum analysis assembly, and is respectively connected with the low-vacuum accumulation leakage detection assembly and the leakage gas mass spectrum analysis assembly through an electric valve; the leakage gas mass spectrum analysis component is used for measuring the rising rate of the partial pressure of leakage gas and is connected with the evacuating unit through an electric valve; the evacuator is used for exhausting the leakage gas and providing vacuum conditions.
Specifically, the high-sensitivity leak detection device based on the low vacuum accumulation method provided by the embodiment of the application can realize accumulation and sampling of the leakage gas He under the low vacuum condition through sampling of the low vacuum accumulation and flow-limiting small holes, can realize measurement of the partial pressure of the tiny leakage gas He through measurement of the partial pressure mass spectrometer 4 and selective air suction of the adsorption pump 15, has the advantages of short leak detection time, high leak detection sensitivity and wide applicable range of detected objects, and can realize 5×10 in a short time (within 30 min) - 13 Pa·m 3 /s-5×10 -9 Pa·m 3 High sensitivity He leak rate measurement in the s leak rate range. The low vacuum accumulation leak detection assembly is mainly used for accumulating leakage gas, a to-be-detected piece to be measured is arranged on the leak detection interface 1, gas generated by leakage of the to-be-detected piece and gas generated by the calibration leak hole 21 enter the low vacuum accumulation chamber 10 through the electromagnetic valve, and the accumulation of the leakage gas can be realized along with the extension of time; the leakage gas sampling assembly is mainly used for leading out leakage gas and consists of two groups of electric valves and current limiting small holes, and according to different accumulated pressures displayed by the low vacuum gauge 9, the leakage gas accumulated in the low vacuum accumulation chamber 10 can be led into the leakage detection chamber 14 by opening different electric valve groups; the leak gas mass spectrum analysis component is mainly used for measuring the leak gas partial pressure rising rate, due to the selective air suction function of the adsorption pump 15, the leak gas in the leak detection chamber 14 can be gradually increased by the sampling gas entering the leak detection chamber 14 along with the extension of the measurement time, the total pressure is not obviously increased, and the partial pressure mass spectrometer 4 gives out the leak gas partial pressure rising rate through measurement; the evacuation unit is mainly used for obtaining high vacuum conditions of the low vacuum accumulation chamber 10 and obtaining extremely high vacuum conditions of the leak detection chamber 14.
Further, the evacuation unit includes a pre-stage mechanical pump 22 and a turbo-molecular pump 24, and a first electromagnetic valve 23 is disposed between the pre-stage mechanical pump 22 and the turbo-molecular pump 24. The first electromagnetic valve 23 is disposed at the inlet end of the pre-stage mechanical pump 22 and the outlet end of the turbomolecular pump 24, and the pre-stage mechanical pump 22 and the turbomolecular pump 24 are used in cooperation, so that a larger vacuum degree can be obtained, and the vacuum degree of the whole device can be adjusted and maintained.
Further, the low vacuum accumulation leak detection assembly comprises a leak detection interface 1, a low vacuum accumulation chamber 10, a calibrated leak 21 and a low vacuum gauge 9, wherein: the leak detection interface 1 is connected with the low vacuum accumulation chamber 10 through a second electromagnetic valve 2; the calibrated leak 21 is connected to the low vacuum accumulation chamber 10 through a third solenoid valve 19; the low vacuum gauge 9 is directly connected with the low vacuum accumulation chamber 10; the low vacuum accumulation chamber 10 is connected to a pre-stage mechanical pump 22 through a fourth solenoid valve 16, and is connected to a turbo molecular pump 24 through a first electrically operated valve 20. The leak detection interface 1 is used for being connected with a to-be-detected piece, and is preferably designed by adopting a quick interface, generally DN16KF, DN25KF and the like, and the leak detection interface needs to be determined according to the volume of a cavity of the actual to-be-detected piece; the low vacuum accumulation chamber 10 is arranged according to the high vacuum requirement, and the background leakage and air release rate can reach 1 multiplied by 10 after being evacuated for 30min -4 Pa·m 3 After accumulation for 5min, the internal pressure is less than or equal to 40Pa; the low vacuum gauge 9 is for displaying the pressure inside the low vacuum accumulation chamber 10; the second electromagnetic valve 2 can control the gas leaked from the to-be-detected piece to enter the low vacuum accumulation chamber 10; the gas generated by the standard leak hole can be controlled to enter the low vacuum accumulation chamber 10 through the third electromagnetic valve 19; the pre-stage mechanical pump 22 can pump the gas in the low vacuum accumulation chamber 10 through the fourth electromagnetic valve 16 and the turbo molecular pump 24 by the first electric valve 20, thereby controlling the vacuum degree in the low vacuum accumulation chamber 10.
Further, the leak gas mass spectrometry assembly includes a leak detection chamber 14, an adsorption pump 15, a partial pressure mass spectrometer 4, and a high vacuum gauge 5, wherein: the adsorption pump 15, the partial pressure mass spectrometer 4 and the high vacuum gauge 5 are all directly connected with the leak detection chamber 14; leak detection chamber 14 is connected to a turbomolecular pump 24 through a second electrically operated valve 18. The leak detection chamber 14 is arranged according to the extremely high vacuum requirement, the high vacuum gauge 5 is used for displaying the pressure in the leak detection chamber 14, the adsorption pump 15 selects a getter pump without obvious pumping action on leakage gas He, the selective pumping function of the adsorption pump 15 is utilized to realize that the total pressure is not obviously increased while the leakage gas partial pressure of the leak detection chamber 14 is gradually increased in the measurement process, the partial pressure mass spectrometer 4 is adopted to realize the measurement of the rising rate of the leakage gas He partial pressure of the leak detection chamber 14, and the turbomolecular pump 24 can pump the gas in the leak detection chamber 14 through the second electric valve 18, so that the control of the vacuum degree of the leak detection chamber 14 is realized.
Further, the leakage gas sampling assembly comprises a first flow restricting orifice 7 and a second flow restricting orifice 12, wherein: one end of the first flow limiting small hole 7 is connected with the low vacuum accumulation chamber 10 through the third electric valve 6, and the other end is connected with the leak detection chamber 14 through the fourth electric valve 8; one end of the second restriction orifice 12 is connected to the low vacuum accumulation chamber 10 through a fifth electrically operated valve 11, and the other end is connected to the leak detection chamber 14 through a sixth electrically operated valve 13. Two sets of flow restricting orifices are provided between the low vacuum accumulation chamber 10 and the leak detection chamber 14 for introducing the leak-indicating gas within the low vacuum accumulation chamber 10 into the leak detection chamber 14 for pressure measurement. In operation, different flow-limiting apertures are selected for gas introduction by controlling different electrically operated valves according to the difference in accumulated pressure in the low vacuum accumulation chamber 10.
Further, the seventh electric valve 3 is further arranged at two ends of the first current limiting small hole 7 in parallel, and the eighth electric valve 17 is further arranged at two ends of the second current limiting small hole 12 in parallel. Because the size of the current-limiting small hole is very small, the air extraction speed is low, and the parallel electric valve is used, the gas accumulated in the previous time can be rapidly extracted through the parallel electric valve in the switching process of different accumulation steps, so that the gas interference in different accumulation processes is avoided, the waiting time is shortened, and the working efficiency is improved.
Further, the nominal leak rate of the standard leak hole is less than or equal to 5 multiplied by 10 -10 Pa·m 3 And/s. The nominal leak rate of the calibrated leak 21 is selected to be 5 x 10- 10 Pa·m 3 Standard leak holes of/s or less, thereby being capable of satisfying 5×10 -13 Pa·m 3 /s-5×10 -9 Pa·m 3 The measurement requirement of the leak rate in the s range.
Further, the first flow restricting orifice 7 has a flow conductance of the order of 1×10 -5 m 3 S, suitable for sampling of the leakage gas of the low vacuum accumulation chamber 10 at a pressure of between 2Pa and 40Pa, the second flow-limiting orifice 12 having a conductance of the order of 5×10 -7 m 3 S, fit toFor sampling of the leakage gas at a pressure of between 0.1Pa and 2Pa in the low vacuum accumulation chamber 10.
Further, the partial pressure mass spectrometer 4 is a quadrupole mass spectrometer, and the mass number range is less than or equal to 100amu. The detection of main gas components in the air can be satisfied by adopting a quadrupole mass spectrometer with smaller mass number.
In addition, the embodiment of the application also provides a method for applying the high-sensitivity leak detection device based on the low vacuum accumulation method, which is used for realizing accumulation of leakage gas in the low vacuum accumulation chamber 10, introducing the low vacuum gas in the low vacuum accumulation chamber 10 into the high vacuum leak detection chamber 14 through a flow limiting small hole, adopting the selective adsorption pump 15 to realize pumping of non-leakage gas in the leak detection chamber 14 and secondary accumulation of leakage gas, adopting the partial pressure mass spectrometer 4 to realize measurement of the partial pressure rising rate of the leakage gas in the leak detection chamber 14, and finally obtaining the leak value of the detected object through comparing the accumulation of leakage gas in the calibrated leak hole 21, the accumulation of background leakage gas and the He partial pressure rising rate of leakage gas in the leak detection chamber 14 obtained in the process of leakage gas accumulation after the detected object is filled with He, and the method specifically comprises the following steps:
step 1: the pre-stage mechanical pump 22, the first electromagnetic valve 23, the turbo molecular pump 24, the second electric valve 18, the high vacuum gauge 5, the seventh electric valve 3, the fourth electric valve 8, the sixth electric valve 13 and the eighth electric valve 17 are sequentially started, and when the high vacuum gauge 5 shows that the pressure of the leak detection chamber 14 is less than 1×10 -3 When Pa, starting the partial pressure mass spectrometer 4, and enabling the adsorption pump 15 to be always in a working state;
step 2: installing a part to be detected on the leak detection interface 1, starting the low vacuum gauge 9, closing the first electromagnetic valve 23, opening the fourth electromagnetic valve 16 and the third electromagnetic valve 19, pre-evacuating the low vacuum accumulation chamber 10, the part to be detected and the calibration leak hole 21, closing the fourth electromagnetic valve 16 and the second electric valve 18 after the low vacuum gauge 9 displays that the pressure of the low vacuum accumulation chamber 10 is less than 10Pa, and vacuumizing the low vacuum accumulation chamber 10 by using the turbo molecular pump 24;
step 3: when the low vacuum gauge 9 shows that the pressure of the low vacuum accumulation chamber 10 is less than 0.1Pa, the first electric valve 20 is closed, the leakage gas of the calibration leakage hole 21 is accumulated for 5min-30min, the pressure of the low vacuum accumulation chamber 10 is less than or equal to 40Pa, the second electric valve 18 is opened simultaneously in the accumulation process, the leakage detection chamber 14 is continuously evacuated by using the turbomolecular pump 24, after the accumulation of the leakage gas of the calibration leakage hole 21 is finished, the second electric valve 18 is closed, and the pressure indication of the low vacuum gauge 9 is observed;
step 4: when the pressure displayed by the low vacuum gauge 9 is more than or equal to 2Pa, the third electric valve 6 is opened, the seventh electric valve 3 and the sixth electric valve 13 are closed, the partial pressure mass spectrometer 4 is used for measuring the rising rate of the partial pressure of the leakage gas He in the leakage detecting chamber 14, the measuring time is between 20s and 1min, after the measuring is finished, the third electric valve 6 is closed, the seventh electric valve 3 and the sixth electric valve 13 are opened, and the equivalent change amount of the partial pressure of the leakage gas He in the low vacuum accumulating chamber 10 is calculated by adopting the following formula:
wherein: Δp He Equivalent variation of the partial pressure of the leakage gas He in the low vacuum accumulation chamber 10, pa/(m) 3 S); r is the rising rate of the He partial pressure of the leak detection chamber 14 obtained by measurement of the partial pressure mass spectrometer 4, and Pa/s; c 1 For the conductance value, m, of the first restriction orifice 7 3 /s；Δ t Indicating a gas accumulation time s for the low vacuum accumulation chamber 10 during measurement;
step 5: when the pressure displayed by the low vacuum gauge 9 is less than 2Pa, the fifth electric valve 11 is opened, the eighth electric valve 17 and the fourth electric valve 8 are closed, the partial pressure mass spectrometer 4 is used for measuring the partial pressure rising rate of the leakage gas He in the leakage detecting chamber 14, the measuring time is between 20s and 1min, after the measuring is finished, the fifth electric valve 11 is closed, the eighth electric valve 17 and the fourth electric valve 8 are opened, and the equivalent change amount of the partial pressure of the leakage gas He in the low vacuum accumulating chamber 10 is calculated by adopting the following formula:
wherein: c 2 For the conductance value, m, of the second flow-restricting orifice 12 3 /s；
Step 6: after the accumulation of the leakage gas of the calibration leakage hole 21 is finished, the third electromagnetic valve 19 is closed, the second electric valve 18 and the first electric valve 20 are opened, the low vacuum accumulation chamber 10 and the leakage detection chamber 14 are evacuated by using the turbo molecular pump 24, and when the low vacuum gauge 9 shows that the pressure of the low vacuum accumulation chamber 10 is less than 0.1Pa, the steps 3-5 are repeated for background leakage gas accumulation;
step 7: after the background leakage gas accumulation is finished, the third electromagnetic valve 19 is closed, the second electric valve 18 and the first electric valve 20 are opened, and the low vacuum accumulation chamber 10 and the leakage detection chamber 14 are evacuated by using the turbo molecular pump 24;
step 8: when the low vacuum gauge 9 shows that the pressure of the low vacuum accumulation chamber 10 is less than 0.1Pa, the flexible cover box is adopted to cover the to-be-detected part, the leakage gas He is filled in the flexible cover box, and the steps 3-5 are repeated to accumulate the leakage gas after the to-be-detected part is filled with the He;
step 9: according to the accumulation of the leakage gas of the calibration leakage hole 21, the accumulation of the background leakage gas and the rising rate of the He partial pressure of the leakage gas of the leakage detecting chamber 14 obtained in the process of accumulating the leakage gas after filling the to-be-detected part with He, the conductance value of the first flow limiting small hole 7 or the second flow limiting small hole 12 is calculated automatically to obtain the leakage value of the to-be-detected part by the calibration value of the calibration leakage hole 21, and the specific calculation requirements are as follows:
when Deltap He2 >3Δp He0 The leak rate value of the to-be-detected piece is calculated by adopting the following formula:
wherein: q is the leak rate value of the to-be-detected piece, pa.m 3 /s；Δp He0 Equivalent variation in pressure of the leakage gas He in the low vacuum accumulation chamber 10, pa/(m), obtained by measurement at the time of accumulation of background leakage gas 3 ·s)；Δp He1 For calibrating the equivalent variation of the He partial pressure of the leakage gas in the low vacuum accumulation chamber 10 obtained by measurement when the leakage gas of the leakage hole 21 is accumulated, pa/(m) 3 ·s)；Δp He2 The equivalent variation of the partial pressure of the leakage gas He in the low vacuum accumulation chamber 10, pa/(m), obtained by measurement when the leakage gas is accumulated after filling He into the workpiece to be detected 3 ·s)；Q sp To calibrate the leak 21 calibration value, pa.m 3 S; gamma is the concentration of the leakage gas He in the flexible cover box when the part to be detected is filled with He for accumulation,%;
when Deltap He2 ≤3Δp He0 Calculating the leak rate value of the to-be-detected part by adopting the following formula:
wherein: q (Q) emin For the device to be effective, the minimum leak-detectable value, pa.m 3 /s。
Therefore, the high-sensitivity leakage detection device and method based on the low-vacuum accumulation method provided by the application combine low-vacuum accumulation, current-limiting small hole sampling and selective air suction and partial pressure measurement, remarkably shorten the leakage detection time while detecting the leakage with high sensitivity, and solve the defect that the higher the leakage detection sensitivity is, the longer the leakage detection time is required in the traditional leakage detection method.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. The utility model provides a high sensitivity leak hunting device based on low vacuum accumulation method which characterized in that includes low vacuum accumulation leak hunting subassembly, leakage gas sampling subassembly, leakage gas mass spectrometry subassembly and evacuation unit, wherein:
the low vacuum accumulation leak detection assembly is used for being connected with a to-be-detected piece to realize accumulation of leakage gas and is connected with the evacuating unit through an electromagnetic valve and an electric valve;
the leakage-indicating gas sampling assembly is used for leading out low-vacuum gas, is arranged between the low-vacuum accumulation leakage detecting assembly and the leakage-indicating gas mass spectrum analysis assembly, and is respectively connected with the low-vacuum accumulation leakage detecting assembly and the leakage-indicating gas mass spectrum analysis assembly through electric valves;
the leakage gas mass spectrometry component is used for measuring the rising rate of the leakage gas partial pressure and is connected with the evacuating unit through an electric valve;
the evacuating unit is used for evacuating the leakage gas and providing vacuum conditions.
2. The apparatus according to claim 1, wherein the evacuation unit includes a pre-mechanical pump and a turbo-molecular pump, and a first electromagnetic valve is provided between the pre-mechanical pump and the turbo-molecular pump.
3. The low vacuum accumulation method based high sensitivity leak detection apparatus as in claim 2 wherein the low vacuum accumulation leak detection assembly comprises a leak detection interface, a low vacuum accumulation chamber, a calibrated leak, and a low vacuum gauge, wherein:
the leak detection interface is connected with the low vacuum accumulation chamber through a second electromagnetic valve;
the calibration leak hole is connected with the low vacuum accumulation chamber through a third electromagnetic valve;
the low vacuum gauge is directly connected with the low vacuum accumulation chamber;
the low vacuum accumulation chamber is connected with the pre-stage mechanical pump through a fourth electromagnetic valve and is connected with the turbomolecular pump through a first electric valve.
4. The apparatus for leak detection with high sensitivity based on the low vacuum accumulation method according to claim 3, wherein the assembly for mass spectrometry of the leaking gas comprises a leak detection chamber, an adsorption pump, a partial pressure mass spectrometer, and a high vacuum gauge, wherein:
the adsorption pump, the partial pressure mass spectrometer and the high vacuum gauge are all directly connected with the leak detection chamber;
the leak detection chamber is connected with the turbomolecular pump through a second electric valve.
5. The apparatus of claim 4, wherein the leakage gas sampling assembly comprises a first flow restricting orifice and a second flow restricting orifice, wherein:
one end of the first flow limiting small hole is connected with the low vacuum accumulation chamber through a third electric valve, and the other end of the first flow limiting small hole is connected with the leakage detection chamber through a fourth electric valve;
one end of the second flow limiting small hole is connected with the low vacuum accumulation chamber through a fifth electric valve, and the other end of the second flow limiting small hole is connected with the leakage detection chamber through a sixth electric valve.
6. The apparatus for detecting leakage with high sensitivity based on the low vacuum accumulation method according to claim 5, wherein the seventh electrically operated valve is further arranged in parallel at both ends of the first flow limiting orifice, and the eighth electrically operated valve is further arranged in parallel at both ends of the second flow limiting orifice.
7. The apparatus for detecting leakage with high sensitivity based on the low vacuum accumulation method according to claim 3, wherein the nominal leakage rate of the standard leakage hole is less than or equal to 5 x 10 -10 Pa·m 3 /s。
8. The apparatus of claim 6, wherein the first orifice has a conductance of the order of 1 x 10 -5 m 3 S, the conductance level of the second flow limiting small hole is 5 multiplied by 10 -7 m 3 /s。
9. The high-sensitivity leak detection device based on the low-vacuum accumulation method according to claim 4, wherein the partial pressure mass spectrometer is a quadrupole mass spectrometer, and the mass number range is less than or equal to 100amu.
10. A method of using the low vacuum accumulation method-based high sensitivity leak detection apparatus as claimed in any one of claims 1 to 9, comprising the steps of:
step 1: sequentially starting the front-stage mechanical pumpA solenoid valve, a turbo molecular pump, a second electric valve, a high vacuum gauge, a seventh electric valve, a fourth electric valve, a sixth electric valve and an eighth electric valve, when the high vacuum gauge shows that the pressure of the leak detection chamber is less than 1×10 -3 Starting a partial pressure mass spectrometer when Pa;
step 2: installing a to-be-detected piece on a leak detection interface, starting a low vacuum gauge, closing a first electromagnetic valve, opening a fourth electromagnetic valve and a third electromagnetic valve, pre-evacuating a low vacuum accumulation chamber, the to-be-detected piece and a calibration leak hole, closing the fourth electromagnetic valve and a second electric valve after the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 10Pa, and vacuumizing the low vacuum accumulation chamber by using a turbo molecular pump;
step 3: when the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 0.1Pa, closing the first electric valve, accumulating the leakage gas of the calibrated leak, wherein the accumulation time is 5-30 min, simultaneously opening the second electric valve, continuously evacuating the leak detection chamber by using the turbo molecular pump, closing the second electric valve after the accumulation of the leakage gas of the calibrated leak is finished, and observing the pressure indication of the low vacuum gauge;
step 4: when the pressure displayed by the low vacuum gauge is more than or equal to 2Pa, opening the third electric valve, closing the seventh electric valve and the sixth electric valve, measuring the rising rate of the partial pressure of the leakage gas He in the leakage detection chamber by using a partial pressure mass spectrometer, wherein the measuring time is between 20s and 1min, closing the third electric valve after the measuring is finished, and opening the seventh electric valve and the sixth electric valve;
step 5: when the pressure displayed by the low vacuum gauge is less than 2Pa, opening a fifth electric valve, closing an eighth electric valve and a fourth electric valve, measuring the rising rate of the partial pressure of the leakage gas He in the leakage detection chamber by using a partial pressure mass spectrometer, wherein the measuring time is between 20s and 1min, closing the fifth electric valve after the measuring is finished, and opening the eighth electric valve and the fourth electric valve;
step 6: closing a third electromagnetic valve, opening a second electric valve and a first electric valve, evacuating the low vacuum accumulation chamber and the leak detection chamber by using a turbo molecular pump, and repeating the steps 3-5 to accumulate background leakage gas after the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 0.1 Pa;
step 7: after the background leakage gas is accumulated, closing a third electromagnetic valve, opening a second electric valve and a first electric valve, and evacuating a low vacuum accumulation chamber and a leakage detection chamber by using a turbomolecular pump;
step 8: when the low vacuum gauge shows that the pressure of the low vacuum accumulation chamber is less than 0.1Pa, coating the to-be-detected part by adopting a flexible cover box, filling leakage gas He into the flexible cover box, and repeating the steps 3-5 to accumulate the leakage gas after filling the He into the to-be-detected part;
step 9: and according to the leakage gas accumulation of the calibrated holes, the background leakage gas accumulation and the rising rate of the He partial pressure of the leakage gas of the leakage detecting chamber obtained in the leakage gas accumulation process after the part to be detected is filled with He, the conductance value of the first current limiting small hole or the second current limiting small hole is used for calibrating the calibrated value of the holes, and the leakage value of the part to be detected is obtained by automatic calculation.
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| CN202310636131.8A CN116858448A (en) | 2023-05-31 | 2023-05-31 | High-sensitivity leakage detection device and method based on low-vacuum accumulation method |
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| CN202310636131.8A CN116858448A (en) | 2023-05-31 | 2023-05-31 | High-sensitivity leakage detection device and method based on low-vacuum accumulation method |
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