CN117686162A - Helium leakage detection method for double O-shaped ring sealed container - Google Patents
Helium leakage detection method for double O-shaped ring sealed container Download PDFInfo
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- 239000001307 helium Substances 0.000 title claims abstract description 194
- 229910052734 helium Inorganic materials 0.000 title claims abstract description 194
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 title claims abstract description 194
- 238000001514 detection method Methods 0.000 title claims abstract description 141
- 238000007789 sealing Methods 0.000 claims abstract description 27
- 230000035945 sensitivity Effects 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 10
- 238000005259 measurement Methods 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 8
- 230000000630 rising effect Effects 0.000 claims description 6
- 238000012360 testing method Methods 0.000 claims description 6
- 238000001819 mass spectrum Methods 0.000 claims description 5
- 230000008859 change Effects 0.000 claims description 3
- 238000012937 correction Methods 0.000 claims description 3
- 230000004044 response Effects 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229920002379 silicone rubber Polymers 0.000 description 2
- 239000004945 silicone rubber Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000004164 analytical calibration Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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Abstract
The invention discloses a helium leakage detection method for a double-O-ring sealed container, which adopts a delay device, the delay device is put into a cylinder body of the double-O-ring sealed container in advance, and helium is released into the cylinder body after a fixed delay time is set, so that the cylinder body is pressurized, the leakage rate detection requirement of the sealed container is ensured, and the purpose of helium leakage detection and sealing detection of the double-O-ring sealed container is realized.
Description
Technical Field
The invention belongs to the technical field of sealed container detection, and particularly relates to a helium leak detection method for a double O-shaped ring sealed container.
Background
The O-shaped sealing ring is the most widely used sealing piece in a hydraulic and pneumatic system, a new product double O-shaped sealing container is developed at present, the double O-shaped sealing ring at the container cover plate is required to be subjected to tightness detection by adopting a helium mass spectrometry detection method, and the leakage rate value requirement is high.
Sealing is the most fundamental problem in helium mass spectrometer leak detector detection equipment, but because the double-O-shaped sealed container has no external charging port, helium cannot be charged into the cylinder, so that helium leak detection sealing detection cannot be carried out, and therefore, research on a leak detection method for the double-O-shaped sealed container is necessary.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides and relates to a helium leak detection method of a double O-shaped ring sealed container.
The invention solves the problem that the cylinder body is pressurized by utilizing the delay device because the cylinder body has no external inflation port, and ensures the leakage rate requirement of the sealed tank so as to achieve the purpose of leakage detection.
In order to solve the technical problems, the technical scheme of the invention is as follows: a helium leak detection method of a double O-ring sealed container comprises the following steps:
step 1: starting a helium mass spectrometer leak detector and calibrating the helium mass spectrometer leak detector;
step 2: connecting the helium mass spectrometer leak detector with a leak detection hole on a cover plate of the double-O-ring sealed container, wherein the leak detection hole is communicated with a space between the double-O-ring;
step 3: vacuumizing a leakage detection hole by using a calibrated helium mass spectrometer leakage detector and calibrating the sensitivity of an initial system;
step 4: helium leak detection inside the double O-shaped ring;
placing a helium-filled delay device in the double-O-ring sealed container, setting delay time, then sealing the double-O-ring sealed container, automatically releasing helium into a cylinder of the double-O-ring sealed container after the delay time is up, maintaining pressure, detecting leakage by helium mass spectrum, reading a value, and obtaining an inner side actual measurement leakage rate Q S ；
Step 5: helium leak detection outside the double O-shaped rings;
after the outer sides of the double O-shaped rings are sealed by the shield, helium is adopted to replace air in the shield,reading the value through a helium mass spectrometer leak detector to obtain the outside actual measurement leak rate Q S is outside ；
Step 6: and taking out the delay device to complete helium leak detection of the double O-ring sealed container.
Preferably, the double-O-ring sealing container comprises a cover plate, a cylinder body and a double-O-ring, wherein the lower end surface of the cover plate is in sealing connection with the upper end surface of the cylinder body, the contact surface of the cover plate and the cylinder body is sealed by the double-O-ring, a leakage detection hole is formed in the cover plate, and the leakage detection hole is communicated with a space between the double-O-ring.
Preferably, the delay device comprises a helium tank, a cover plate, a first adapter, a second adapter, a valve, a pressure gauge, an electromagnetic valve, a direct current power supply and a delay device, wherein the top of the helium tank is connected with the cover plate in a sealing manner, the cover plate is provided with the first adapter and the second adapter, the first adapter is connected with the pressure gauge, the second adapter is connected with the valve, and the valve is respectively and electrically connected with the electromagnetic valve, the direct current power supply and the delay device.
Preferably, the step 2 specifically includes: the helium mass spectrometer leak detector is connected with the leak detection hole of the double O-shaped ring sealed container through a three-way valve, a first connecting end of the three-way valve is connected with the detection valve of the helium mass spectrometer leak detector, a second connecting end of the three-way valve is connected with the leak detection hole, and a third connecting end of the three-way valve is connected with the standard leak.
Preferably, the step 4 includes:
step 4-1: opening the valve, evacuating the helium tank, and filling with pressure P 1 Closing a valve, connecting a pressure gauge by using a first adapter, connecting an electromagnetic valve, a direct current power supply and a delayer by using a second adapter, and forming a delay device, wherein the delay time is set to be 30-60 minutes;
step 4-2: the delay device is integrally put into a cylinder, a double O-shaped ring sealing container is sealed, helium is automatically released into the cylinder after the time arrives, and after the helium is released, the rising pressure P of the container after the helium tank releases the helium is calculated according to the following formula 2 And according to the rising pressure P of the container after releasing helium from the helium tank 2 Calculating the actually measured helium concentration C in the detected system during detection;
P 1 ×V 1 ＝P 2 ×(V 2 －V 1 )
P 2 ＝P 1 ×V 1 ÷(V 2 －V 1 )
C＝P 2 ÷(P 2 +P)×100％
wherein:
P 1 : the pressure of the helium tank, pa;
V 1 : volume of helium tank, m 3 ；
V 2 : volume of container to be inspected, m 3 ；
P 2 : the helium tank releases helium gas, and then the container rises pressure Pa;
c: the concentration of the actually measured helium in the detected system is detected,%;
p: standard atmospheric pressure, 10 5 Pa；
Step 4-3: vacuumizing a leak detection hole by using a helium mass spectrometer leak detector, opening a standard leak until a signal of the helium mass spectrometer leak detector is stable when the debugged helium mass spectrometer leak detector is in a leak detection state, and recording a reading value M of the helium mass spectrometer leak detector 1 when a time difference from the opening time of the leak detection hole to the time when an output signal reaches stability is the response time of the system 1 The method comprises the steps of carrying out a first treatment on the surface of the Closing the leak detection hole, and recording a background value M after the reading of the helium mass spectrometer leak detector is stable 2 Initial System sensitivity S 1 Namely the inner side measured leak rate Q S Obtaining the inner side actually measured leak rate Q through a first leak detection formula S The first leak detection formula is:
S 1 ＝Q/(M 1 -M 2 )
wherein:
S 1 : initial system sensitivity, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s。
Preferably, when the arrangement of the helium mass spectrometer leak detector changes, or the calibrated leak has changed, a recalibration is required, after the initial sensitivity calibration of the system is completed, the standard leak is closed, and the output reading of the helium mass spectrometer leak detector is measured with the delay device deflatedNumber M 3 The standard leak is opened again and the helium mass spectrometer leak detector output is increased to reading M 4 Obtaining the final sensitivity S 2 ：
S 2 ＝Q/(M 4 -M 3 )
Wherein:
S 2 : final system sensitivity, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s。
Preferably, when the final system sensitivity is reduced below 35% of the initial system sensitivity, the helium mass spectrometer leak detector should be cleaned or repaired, recalibrated and then re-detected;
for the case where the output signal does not change, i.e. M 2 ＝M 3 Inner side measured leak rate Q S Should be recorded as acceptable for the output signal M 3 When the leakage rate is changed, the leakage rate Q is measured at the inner side S Calculated according to the following formula:
Q S ＝S 2 (M 3 -M 2 )/C
S 2 : final system sensitivity, pa.m 3 /s；
Q S : the leak rate measured at the inner side, pa.m 3 /s；
C: measured helium concentration in the inspected system,%.
Preferably, the step 5 includes:
step 5-1: wrapping a shield outside the double O-shaped rings and sealing, then replacing gas in the shield with helium, and measuring the concentration of the helium to reach more than 80%;
step 5-2: output reading M using helium mass spectrometer leak detector 3 outside And M 4 outside of Calculating to obtain the outside actual measurement leak rate Q through a second leak detection formula s is outside The second leak detection formula is:
S 2 outside of ＝Q/(M 4 outside of -M 3 outside )
Q s is outside ＝S 2 outside of (M 3 outside -M 2 )/C Outer part
Wherein:
S 2 outside of : outboard final System sensitivity, pa.m 3 /s；
Q s is outside : outside measured leak rate, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s；
C Outer part : measured helium concentration in the outer shroud,%.
Preferably, the temperature T is calibrated with the standard leak Q at the time of testing 0 When the phase difference is generated, the leak rate value Q of the standard leak hole is required to be corrected, and the correction formula is as follows:
Q 1 ＝Q[1+α(T-T 0 )]
alpha: a temperature coefficient;
q: standard leak rate, pa.m 3 /s；
Q 1 : corrected leak rate, pa.m 3 /s。
Compared with the prior art, the invention has the advantages that:
(1) The invention discloses a helium leakage detection method of a double-O-ring sealed container, which adopts a delay device, the delay device is put into a cylinder in advance, and helium is released into the cylinder after fixed delay time is set, so that the cylinder is pressurized, the leakage rate detection requirement of the sealed container is ensured, and the purpose of helium leakage detection and sealing detection of the double-O-ring sealed container is realized;
(2) When the helium leak detection method is used for detecting the helium leak in and out of the double O-shaped ring, the helium mass spectrometer leak detector displays a leak rate which is similar to the background value of a detection system and is far smaller than the system calibration value of a standard leak hole in the detection time of less than 5 minutes, and the leak rate detection result in and out of the double O-shaped ring is judged to be in accordance with the requirement of the sealed container on the leak rate;
(3) According to the invention, the delay device is skillfully designed, the detection time of the sealed container is reasonably selected, and the helium leak detection method is adopted in the process, so that the detection requirement of the double O-shaped ring sealed container is met, the detection efficiency is greatly improved, the production and manufacturing cost of products is reduced, and a foundation is laid for batch detection and manufacturing;
(4) The helium leak detection method has the advantages of low investment, convenient operation and high reliability, fills the blank of helium leak detection of the double O-shaped ring sealed special structure container, and provides technical guarantee for mass production of the product.
Drawings
FIG. 1 is a flow chart of a helium leak detection method for a double O-ring sealed container of the present invention;
FIG. 2 is a schematic diagram of a helium leak detection method for a double O-ring sealed container according to the present invention;
fig. 3 is a schematic structural view of the delay device of the present invention.
Reference numerals illustrate:
1. helium mass spectrometer leak detector 2, double O-ring sealed container 3, delay device 4, shield;
1-1 parts of detection valve, 1-2 parts of three-way valve, 1-3 parts of standard leak hole;
2-1 parts of cover plate, 2-2 parts of cylinder, 2-3 parts of double O-shaped rings;
2-1-1, leak detection holes;
3-1 parts of helium tank, 3-2 parts of cover plate, 3-3 parts of adapter, 3-4 parts of second adapter, 3-5 parts of valve, 3-6 parts of pressure gauge, 3-7 parts of electromagnetic valve, 3-8 parts of direct current power supply, 3-9 parts of delay device.
Detailed Description
The following describes specific embodiments of the present invention with reference to examples:
it should be noted that the structures, proportions, sizes and the like illustrated in the present specification are used for being understood and read by those skilled in the art in combination with the disclosure of the present invention, and are not intended to limit the applicable limitations of the present invention, and any structural modifications, proportional changes or size adjustments should still fall within the scope of the disclosure of the present invention without affecting the efficacy and achievement of the present invention.
Example 1
As shown in FIG. 1, the invention discloses a helium leak detection method of a double O-ring sealed container, which comprises the following steps:
step 1: starting the helium mass spectrometer leak detector 1 and calibrating the helium mass spectrometer leak detector 1;
step 2: connecting the helium mass spectrometer leak detector 1 with a leak detection hole 2-1-1 on a cover plate 2-1 of a double O-ring sealed container 2, and communicating the leak detection hole 2-1-1 with a space between the double O-rings 2-3;
step 3: vacuumizing the leak detection hole 2-1-1 by using the calibrated helium mass spectrometer leak detector 1 and calibrating the sensitivity of the initial system;
step 4: helium leak detection inside the double O-shaped ring;
placing a helium-filled delay device 3 in the double-O-ring sealed container 2, setting delay time, then sealing the double-O-ring sealed container 2, automatically releasing helium into a cylinder 2-2 of the double-O-ring sealed container 2 after the delay time is up, maintaining pressure, reading the value through a helium mass spectrometer leak detector 1, and obtaining the inner measured leak rate Q S ；
Step 5: helium leak detection outside the double O-shaped rings;
after the outer sides of the double O-shaped rings 2-3 are sealed by using a shield 4, helium is adopted to replace air in the shield 4, and the value is read by a helium mass spectrometer leak detector 1 to obtain the outer side actual measurement leak rate Q S is outside ；
Step 6: and taking out the delay device 3 to finish helium leakage detection of the double O-ring sealed container 2.
Example 2
Preferably, as shown in fig. 2, the double-O-ring sealed container 2 includes a cover plate 2-1, a cylinder 2-2 and a double-O-ring 2-3, the lower end surface of the cover plate 2-1 is in sealing connection with the upper end surface of the cylinder 2-2, the contact surface of the cover plate 2-1 and the cylinder 2-2 is sealed by the double-O-ring 2-3, the cover plate 2-1 is provided with a leak detection hole 2-1-1, and the space between the leak detection hole 2-1-1 and the double-O-ring 2-3 is communicated.
Because of the different sizes of the silicone rubber O-rings, helium gas has a permeation effect on the silicone rubber under certain concentration and pressure, and in order to reduce the influence of permeation on helium leakage detection, the test helium leakage detection time is controlled to be before the permeation effect time of helium gas on the O-rings (generally less than 5 minutes).
Example 3
Preferably, as shown in fig. 3, the delay device 3 comprises a helium tank 3-1, a cover plate 3-2, a first adapter 3-3, a second adapter 3-4, a valve 3-5, a pressure gauge 3-6, an electromagnetic valve 3-7, a direct current power supply 3-8 and a delay device 3-9, wherein the top of the helium tank 3-1 is connected with the cover plate 3-2 in a sealing manner, the cover plate 3-2 is provided with the first adapter 3-3 and the second adapter 3-4, the first adapter 3-3 is connected with the pressure gauge 3-6, the second adapter 3-4 is connected with the valve 3-5, and the valve 3-5 is respectively and electrically connected with the electromagnetic valve 3-7, the direct current power supply 3-8 and the delay device 3-9.
The whole size of the delay device 3 is smaller than that of the cylinder 2-2, delay time is set through the delay device 3-9, the delay time is generally 30-60 minutes, and after the delay time is up, the electromagnetic valve 3-7 is opened, so that helium in the helium tank 3-1 is released.
Example 4
Preferably, the step 2 specifically includes: the helium mass spectrometer leak detector 1 is connected with a leak detection hole 2-1-1 of a double O-ring sealed container 2 through a three-way valve 1-2, a first connecting end of the three-way valve 1-2 is connected with a detection valve 1-1 of the helium mass spectrometer leak detector 1, a second connecting end of the three-way valve 1-2 is connected with the leak detection hole 2-1-1, and a third connecting end of the three-way valve 1-2 is connected with a standard leak 1-3.
The standard leak 1-3 needs to be calibrated to obtain the standard leak rate Q, and the calibration process is an existing method, which is not repeated in the application.
Example 5
Preferably, the step 4 includes:
step 4-1: the valve 3-5 is opened, the helium tank 3-1 is evacuated, and then the pressure P is filled 1 Closing a valve 3-5, connecting a pressure gauge 3-6 by using a first adapter 3-3, connecting an electromagnetic valve 3-7, a direct current power supply 3-8 and a delayer 3-9 by using a second adapter 3-4 through the valve 3-5 to form a delay device 3, and setting delay time to be 30-60 minutes;
step 4-2: the delay device 3 is integrally put into the cylinder 2-2, the double O-shaped ring sealing container 2 is sealed, helium is automatically released into the cylinder 2-2 after the time arrives, after the helium is released, the rising pressure P of the container after the helium tank releases the helium is calculated according to the following formula 2 And according to the rising pressure P of the container after releasing helium from the helium tank 2 Calculating the actual measured helium concentration in the detected system during detectionA degree C;
P 1 ×V 1 ＝P 2 ×(V 2 －V 1 )
P 2 ＝P 1 ×V 1 ÷(V 2 －V 1 )
C＝P 2 ÷(P 2 +P)×100％
wherein:
P 1 : the pressure of the helium tank, pa;
V 1 : volume of helium tank, m 3 ；
V 2 : volume of container to be inspected, m 3 ；
P 2 : the helium tank releases helium gas, and then the container rises pressure Pa;
c: the concentration of the actually measured helium in the detected system is detected,%;
p: standard atmospheric pressure, 10 5 Pa；
Step 4-3: vacuumizing the detection hole 2-1-1 by using the helium mass spectrometer leak detector 1, enabling the debugged helium mass spectrometer leak detector 1 to be in a leak detection state, opening the standard leak hole 1-3 until the signal of the helium mass spectrometer leak detector 1 is stable, and recording the reading value M of the helium mass spectrometer leak detector 1 when the time difference from the opening time of the detection hole 2-1-1 to the time when the output signal reaches the stable is the response time of the system 1 The method comprises the steps of carrying out a first treatment on the surface of the Closing the leak detection hole 2-1-1, and recording the background value M after the helium mass spectrometer leak detector 1 is stable in reading 2 Initial System sensitivity S 1 Namely the inner side measured leak rate Q S Obtaining the inner side actually measured leak rate Q through a first leak detection formula S The first leak detection formula is:
S 1 ＝Q/(M 1 -M 2 )
wherein:
S 1 : initial system sensitivity, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s。
When the final system sensitivity decreases below 35% of the initial system sensitivity, helium mass spectrometer leak detector 1 should be cleaned or repaired, recalibrated and then re-detected;
for the case where the output signal does not change, i.e. M 2 ＝M 3 Inner side measured leak rate Q S Should be recorded as acceptable for the output signal M 3 When the leakage rate is changed, the leakage rate Q is measured at the inner side S Calculated according to the following formula:
Q S ＝S 2 (M 3 -M 2 )/C
S 2 : final system sensitivity, pa.m 3 /s；
Q S : the leak rate measured at the inner side, pa.m 3 /s；
C: measured helium concentration in the inspected system,%.
Example 6
The step 5 comprises the following steps:
step 5-1: wrapping the shield 4 outside the double O-shaped rings 2-3 and sealing, then replacing the gas in the shield 4 with helium, and measuring the concentration of the helium to more than 80%;
step 5-2: output reading M using helium mass spectrometer leak detector 1 3 outside And M 4 outside of Calculating to obtain the outside actual measurement leak rate Q through a second leak detection formula s is outside The second leak detection formula is:
S 2 outside of ＝Q/(M 4 outside of -M 3 outside )
Q s is outside ＝S 2 outside of (M 3 outside -M 2 )/C Outer part
Wherein:
S 2 outside of : outboard final System sensitivity, pa.m 3 /s；
Q s is outside : outside measured leak rate, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s；
C Outer part : measured helium concentration in the outer shroud,%.
Preferably, the temperature T is calibrated with the standard leak Q at the time of testing 0 When the phase difference is generated, the leak rate value Q of the standard leak hole is required to be corrected, and the correction formula is as follows:
Q 1 ＝Q[1+α(T-T 0 )]
alpha: a temperature coefficient;
q: standard leak rate, pa.m 3 /s；
Q 1 : corrected leak rate, pa.m 3 /s。
When the temperature T in the test is different from the standard leak calibration temperature, the leak rate value Q of the standard leak is required to be corrected.
Example 7
The helium leak detection method is used for detecting a certain double O-shaped ring sealed container, and the actual measurement data are shown in the following table:
TABLE 1 detection data for inside of double O-rings
M in detection 3 ≈M 2 ，Q s Is lower than the detectable range of the system, is detected to be qualified, and is Q s Is 7.5X10 -10 Pa.m 3 And/s, directly judging and not participating in calculation when M3 is approximately equal to M2.
TABLE 2 detection data for outside of double O-rings
M in detection 3 ≈M 2 ，Q s The outside is lower than the detectable range of the system, and the detection is qualified, Q s Is 5.4X10 -10 Pa.m 3 S), at M 3 ≈M 2 And in the case, the calculation is directly judged and not participated.
A large number of experiments prove that the delay device 3 meets the helium leak detection technical requirement.
The working principle of the invention is as follows:
as shown in fig. 1, the invention discloses a helium leak detection method of a double O-ring sealed container, which is characterized in that equipment is preheated according to the specification of a helium mass spectrometer leak detector 1, instrument calibration is carried out according to requirements, the double O-ring sealed container 2 is connected with the helium mass spectrometer leak detector 1 according to a detection principle diagram, the debugged helium mass spectrometer leak detector 1 is used for vacuumizing the double O-ring 2-3 space of a sealed container cover and carrying out initial system sensitivity calibration (if the arrangement of the helium mass spectrometer leak detector 1 is changed or calibrated leak is changed, the calibration should be carried out again), and the helium leak detection on the inner side of the double O-ring is carried out: a delay device 3 filled with helium is placed in the cylinder, the time of the delay device is set, the helium is automatically released into the cylinder after the time arrives, pressure maintaining is carried out according to standard requirements after the helium is released, and detection data on the inner side of the double O-shaped ring are measured; detection of the outer side of the double O-shaped ring: after the outer side of the double O-shaped ring is sealed by a shield 4, helium replacement is adopted, the concentration of the measured helium is not lower than a standard required value, the detection duration is kept until an output signal is stable, an instrument output reading is recorded, and the detection leakage rate is calculated.
The invention discloses a helium leakage detection method for a double-O-ring sealed container, which adopts a delay device, the delay device is put into a cylinder in advance, and helium is released into the cylinder after a fixed delay time is set, so that the cylinder is pressurized, the leakage rate detection requirement of the sealed container is ensured, and the purpose of helium leakage detection and sealing detection of the double-O-ring sealed container is realized.
When the helium leak detection method is used for detecting the helium leak on the inner side of the double O-shaped ring, the helium mass spectrometer leak detector displays a leak rate which is similar to the background value of a detection system and is far smaller than the system calibration value of a standard leak hole in the limited detection time, and the leak rate detection result on the inner side of the double O-shaped ring is judged to meet the requirement of the sealed container on the leak rate.
When the helium leak detection method is used for detecting the helium outside the double O-shaped ring, the helium mass spectrometer leak detector displays a leak rate which is similar to the background value of a detection system and is far smaller than the system calibration value of a standard leak hole in the limited detection time, and the leak rate detection result outside the double O-shaped ring is judged to meet the requirement of the sealed container on the leak rate.
According to the invention, the delay device is skillfully designed, the detection time of the sealed container is reasonably selected, and the helium leak detection method is adopted in the process, so that the detection requirement of the double O-shaped ring sealed container is met, the detection efficiency is greatly improved, the production and manufacturing cost of products is reduced, and a foundation is laid for batch detection and manufacturing.
The helium leak detection method has the advantages of low investment, convenient operation and high reliability, fills the blank of helium leak detection of the double O-shaped ring sealed special structure container, and provides technical guarantee for mass production of the product.
Considering that the tightness test is to detect the tightness of the cylinder under the combined action of the pretightening force of the O-shaped ring, the flange and the bolt, the tightness of the cylinder is basically the same under the same conditions, so that after the leakage detection of the helium of the cylinder is completed, the helium time-delay release device is taken out, and the cover plate is reinstalled according to the requirement, thereby ensuring the final tightness.
While the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes may be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.
Many other changes and modifications may be made without departing from the spirit and scope of the invention. It is to be understood that the invention is not to be limited to the specific embodiments, but only by the scope of the appended claims.
Claims (9)
1. The helium leak detection method for the double O-shaped ring sealed container is characterized by comprising the following steps of:
step 1: starting the helium mass spectrometer leak detector (1) and calibrating the helium mass spectrometer leak detector (1);
step 2: connecting a helium mass spectrometer leak detector (1) with a leak detection hole (2-1-1) on a cover plate (2-1) of a double O-ring sealed container (2), wherein the leak detection hole (2-1-1) is communicated with a space between the double O-ring (2-3);
step 3: vacuumizing the leak detection hole (2-1-1) by using the calibrated helium mass spectrometer leak detector (1) and calibrating the sensitivity of the initial system;
step 4: helium leak detection inside the double O-shaped ring;
placing the filling in a double O-ring sealed container (2)A helium delay device (3) for setting delay time, then sealing the double O-ring sealing container (2), automatically releasing helium into the cylinder (2-2) of the double O-ring sealing container (2) after the delay time is up, maintaining pressure, reading the value through a helium mass spectrometer leak detector (1), and obtaining the inner side actual measurement leak rate Q S ；
Step 5: helium leak detection outside the double O-shaped rings;
after the outer sides of the double O-shaped rings (2-3) are sealed by a shield (4), air in the shield (4) is replaced by helium, and the value is read by a helium mass spectrometer leak detector (1) to obtain the outer side actual measurement leak rate Q S is outside ；
Step 6: and taking out the delay device (3) to finish helium leakage detection of the double O-ring sealed container (2).
2. The helium leak detection method of the double-O-ring sealed container according to claim 1, wherein the double-O-ring sealed container (2) comprises a cover plate (2-1), a cylinder body (2-2) and a double-O-ring (2-3), the lower end face of the cover plate (2-1) is in sealing connection with the upper end face of the cylinder body (2-2), the contact face of the cover plate (2-1) and the cylinder body (2-2) is sealed through the double-O-ring (2-3), a leak detection hole (2-1-1) is formed in the cover plate (2-1), and the leak detection hole (2-1-1) is communicated with a space between the double-O-ring (2-3).
3. The helium leak detection method of the double O-ring sealed container according to claim 2, wherein the delay device (3) comprises a helium tank (3-1), a cover plate (3-2), a first adapter (3-3), a second adapter (3-4), a valve (3-5), a pressure gauge (3-6), an electromagnetic valve (3-7), a direct current power supply (3-8) and a delayer (3-9), the cover plate (3-2) is connected to the top of the helium tank (3-1) in a sealing mode, the cover plate (3-2) is provided with the first adapter (3-3) and the second adapter (3-4), the first adapter (3-3) is connected with the pressure gauge (3-6), the second adapter (3-4) is connected with the valve (3-5), and the valve (3-5) is electrically connected with the electromagnetic valve (3-7), the direct current power supply (3-8) and the delayer (3-9) respectively.
4. A helium leak detection method for a double O-ring sealed container according to claim 3, wherein said step 2 is specifically: the helium mass spectrometer leak detector (1) is connected with a leak detection hole (2-1-1) of the double O-shaped ring sealed container (2) through a three-way valve (1-2), a first connecting end of the three-way valve (1-2) is connected with a detection valve (1-1) of the helium mass spectrometer leak detector (1), a second connecting end of the three-way valve (1-2) is connected with the leak detection hole (2-1-1), and a third connecting end of the three-way valve (1-2) is connected with a standard leak (1-3).
5. A method of helium leak detection of a double O-ring sealed container according to claim 3, wherein said step 4 comprises:
step 4-1: opening the valve (3-5), evacuating the helium tank (3-1), and filling with pressure P 1 Closing a valve (3-5), connecting a pressure gauge (3-6) by using a first adapter (3-3), connecting an electromagnetic valve (3-7), a direct current power supply (3-8) and a delayer (3-9) by using a second adapter (3-4) through the valve (3-5) to form a delay device (3), and setting the delay time to be 30-60 minutes;
step 4-2: the delay device (3) is integrally placed in the cylinder (2-2), the double O-shaped ring sealing container (2) is sealed, helium is automatically released into the cylinder (2-2) after the time arrives, and after the helium is released, the rising pressure P of the container after the helium tank releases the helium is calculated according to the following formula 2 And according to the rising pressure P of the container after releasing helium from the helium tank 2 Calculating the actually measured helium concentration C in the detected system during detection;
P 1 ×V 1 ＝P 2 ×(V 2 －V 1 )
P 2 ＝P 1 ×V 1 ÷(V 2 －V 1 )
C＝P 2 ÷(P 2 +P)×100％
wherein:
P 1 : the pressure of the helium tank, pa;
V 1 : volume of helium tank, m 3 ；
V 2 : volume of container to be inspected, m 3 ；
P 2 : the helium tank releases helium gas, and then the container rises pressure Pa;
c: the concentration of the actually measured helium in the detected system is detected,%;
p: standard atmospheric pressure, 10 5 Pa；
Step 4-3: vacuumizing a leak detection hole (2-1-1) by using a helium mass spectrum leak detector (1), opening a standard leak hole (1-3) until a signal of the helium mass spectrum leak detector (1) is stable, obtaining response time of a system after a time difference from the opening time of the leak detection hole (2-1-1) to the time when an output signal reaches stability is obtained, and recording a reading value M of the helium mass spectrum leak detector (1), wherein the debugged helium mass spectrum leak detector (1) is in a leak detection state 1 The method comprises the steps of carrying out a first treatment on the surface of the Closing the leak detection hole (2-1-1), and recording the background value M after the helium mass spectrometer leak detector (1) has stable reading 2 Initial System sensitivity S 1 Namely the inner side measured leak rate Q S Obtaining the inner side actually measured leak rate Q through a first leak detection formula S The first leak detection formula is:
S 1 ＝Q/(M 1 -M 2 )
wherein:
S 1 : initial system sensitivity, pa.m3/s;
q: standard leak rate, pa.m 3 /s。
6. A method of helium leak detection with a double O-ring sealed container according to claim 5, characterized in that when the arrangement of the helium mass spectrometer leak detector (1) changes, or there is a variation in the calibrated leak, a recalibration is required, after the initial sensitivity calibration of the system is completed, the standard leak (1-3) is closed, and in the case of deflation of the delay means (3), the output reading M of the helium mass spectrometer leak detector (1) is measured 3 The standard leak holes (1-3) are opened, and the output of the helium mass spectrometer leak detector (1) is increased to a reading M 4 Obtaining the final sensitivity S 2 ：
S 2 ＝Q/(M 4 -M 3 )
Wherein:
S 2 : final system sensitivity, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s。
7. A method of helium leak detection with a double O-ring sealed vessel according to claim 6, wherein the helium mass spectrometer leak detector (1) should be cleaned or repaired, recalibrated and then re-inspected when the final system sensitivity is reduced below 35% of the initial system sensitivity;
for the case where the output signal does not change, i.e. M 2 ＝M 3 Inner side measured leak rate Q S Should be recorded as acceptable for the output signal M 3 When the leakage rate is changed, the leakage rate Q is measured at the inner side S Calculated according to the following formula:
Q S ＝S 2 (M 3 -M 2 )/C
S 2 : final system sensitivity, pa.m 3 /s；
Q S : the leak rate measured at the inner side, pa.m 3 /s；
C: measured helium concentration in the inspected system,%.
8. The helium leak detection method of a double O-ring sealed container according to claim 6, wherein said step 5 comprises:
step 5-1: wrapping a shield (4) outside the double O-shaped rings (2-3) and sealing, and then replacing the gas in the shield (4) with helium, wherein the concentration of the helium is measured to be more than 80%;
step 5-2: output reading M using helium mass spectrometer leak detector (1) 3 outside And M 4 outside of Calculating to obtain the outside actual measurement leak rate Q through a second leak detection formula s is outside The second leak detection formula is:
wherein:
outboard final System sensitivity, pa.m 3 /s；
Outside measured leak rate, pa.m 3 /s；
Q: standard leak rate, pa.m 3 /s；
C Outer part : measured helium concentration in the outer shroud,%.
9. The helium leak detection method for a double O-ring sealed container according to claim 8, wherein the temperature T is calibrated with the standard leak Q at the time of testing 0 When the phase difference is generated, the leak rate value Q of the standard leak hole is required to be corrected, and the correction formula is as follows:
Q 1 ＝Q[1+α(T-T 0 )]
alpha: a temperature coefficient;
q: standard leak rate, pa.m 3 /s；
Q 1 : corrected leak rate, pa.m 3 /s。
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