Typical Measurement Times with T-Guard
The T-Guard Helium Leak Detection Sensor automatically measures helium leak rates without using a vacuum chamber. It is less sensitive than a helium measurement in vacuum, but about 100 times more sensitive than air leak test (pressure decay) and water bath (bubble test). Total measurement times however, are comparable to the other methods, given that the desired leak rate matches T-Guard's sensitivity.
Fast Measurements Without the Vacuum Chamber
The recommended minimum measurement time with T-Guard is 11 seconds. In this time, T-Guard can measure highly repeatable a leak rate of 1x10-3 mbar l/s (0.06 sccm or 1x10-4 Pa m³/s or 1x10-3 atm cc/s) in a 10 liter chamber. As you may already know, this is impossible with pressure decay. The water bath test is extremely operator dependent; therefore this leak rate will usually not be detected at all. (For more information, watch this water bath testing video)
Of course, you could measure this leak rate with helium in a vacuum chamber, but it needs fast, large pumps to do this in 11 seconds, so T-Guard is the much more cost efficient solution.
If the production volume is lower and you can spend more time on the leak test, T-Guard can also measure a leak rate as small as 1x10-4 mbar l/s (0.006 sccm or 1x10-5 Pa m³/s or 1x10-4 atm cc/s) in a 10 liter chamber in one minute.
To estimate the T-Guard measurement time, it is useful to relate the free chamber volume (total chamber volume minus volume of test part) to the desired leak rate:
Examples are:
For more information on how T-Guard can quickly measure leak rates without a vacuum chamber, contact your local INFICON support center. You can also email us at reachus@inficon.com, or click here to request someone contact you.
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