Argon Helium Mass Spectrometry Leak Test Method
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Solution Overview
Problem
Current cumulative helium mass spectrometric combination tests face a dilemma in achieving stricter criteria for fine-leak tests while expanding cavity volume and maintaining maximum test-waiting times, due to limitations in helium gas partial pressure and sensitivity, which restricts the removal of absorbed helium and argon.
Innovation Solution
Employing argon gas as the gross-leak tracer gas, allowing for a lower minimum detectable equivalent standard leak rate and longer maximum test-waiting times, thereby expanding the range of cavity volume and criterion for measured leak rates in fine-leak tests, using a helium-argon prefilling or pressuring method with flexible schemes to accommodate varying test conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If helium gas is used as tracer gas for gross-leak test, then the test sensitivity is sufficient, but the maximum test-waiting time is limited and the cavity volume range is restricted
Solution Approach 1:
The patent changes the tracer gas from helium to argon for gross-leak testing. This parameter change increases the partial pressure of the tracer gas in air (from 0.533 Pa for helium to 946 Pa for argon), which extends the maximum test-waiting time while maintaining adequate test sensitivity for gross-leak detection.
Solution Approach 2:
The patent introduces a two-stage testing approach where argon serves as the intermediary tracer gas for gross-leak detection, followed by helium for fine-leak detection. This intermediary approach allows the system to benefit from both gases: argon's high partial pressure for extended waiting time and helium's superior sensitivity for fine-leak measurement.
2Measurement precision
If the criterion for helium measured leak rate of fine-leak test is made stricter, then the fine-leak detection precision is improved, but the maximum test-waiting time must be extended which conflicts with the limited argon removal time
Solution Approach 1:
The patent segments the leak detection process into two distinct stages: gross-leak testing using argon and fine-leak testing using helium. This segmentation allows each stage to use the optimal tracer gas for its specific purpose, enabling stricter fine-leak criteria without requiring extended waiting times that would conflict with argon removal requirements.
Solution Approach 2:
The patent uses argon as an intermediary for gross-leak detection before fine-leak testing. This intermediary approach allows the system to remove argon and prepare for fine-leak testing with helium, thereby achieving stricter fine-leak detection criteria without being constrained by extended waiting time requirements.
3Duration of action of moving object
If the minimum detectable equivalent standard leak rate L0 is increased, then the maximum test-waiting time is extended, but the removal of surficially absorbed helium cannot meet the test requirement
Solution Approach 1:
The patent changes the tracer gas from helium to argon for gross-leak testing. This parameter change allows for a lower minimum detectable equivalent standard leak rate L0 while extending the maximum test-waiting time, because argon's higher partial pressure in air enables sufficient detection sensitivity without requiring long waiting times for absorbed gas removal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively lengthens the maximum test-waiting time for fine-leak tests, ensures stricter criteria for helium leak rate removal, and expands the adapted range of cavity volumes and leak rates, enhancing the practicality and applicability of cumulative helium mass spectrometric combination tests.
Implementation Method 1
cumulative helium mass spectrometric combination test
Implementation Method 2
mass spectrometric leak detector
Implementation Method 3
employing the cryogenic pump technique
Implementation Method 4
leak rate of argon gas is 562 times as that of helium gas for the same gross-leak aperture
Data Source
AI summary
The present invention discloses a method of cumulative helium mass spectrometric combination test by using argon gas as gross-leak tracer gas, and specifically gives the procedure for this gross-leak and fine-leak combination test, comprising steps and methods of selecting helium-argon prefilling method or helium-argon pressuring method, fixed or flexible scheme and the criterion RAr0max for argon measured leak rate of gross-leak test according to the rigour grade THemin, cavity volume, leak rate of surficially absorbed helium and argon and the history of the test of a component under test; designing time for pressuring of helium-argon pressuring method, the maximum test-waiting time of fine-leak test and the criterion for helium measured leak rate, helium-argon prefilling and helium-argon pressuring, removing absorbed helium and argon gas, gross-leak test, fine-leak test and complementally testing bigger gross leak, which enhances the sensitivity of gross-leak test, lengthens the maximum test-waiting time of fine-leak test, tremendously expands the range of adapted cavity volume and criterion for measured leak rate of fine-leak test, thus making the cumulative helium mass spectrometric combination test more applicable, convenient and practical.