Hard vacuum test.
The hard vacuum test (using helium as tracer gas) is the most precise method to automatically leak test a product. This test can be performed with active helium supply or with products that are pre-filled with helium. Verborg Engineering B.V. is able to do both of these versions, on this page the pre-filled products will be explained. The example product for this page will be tight head steel drums.
How it works
The tight head steel drums arrive closed in a vacuum chamber, these are filled with 1% helium. In the vacuum chamber, the air gets extracted to around 1mbar absolute pressure. After this, a sample of the current air in that chamber is taken. If some of the helium in the drums escaped to the vacuum chamber during this process, it will be measured.
Other tracer gasses are also applicable for this leak testing method, for the most accurate results helium is the most applicable, however this is also the most expensive tracer gas.
Working principal sketch:
Pros:
- Very precise (10-8 mbar*l/s).
- Product stays clean during test.
- No operators required, fully automatic solutions available.
- High capacity rate for zero-defect production lines.
Cons:
- Vacuum and tracer gas required.
- Relatively expensive.
- Position of leak can not be identified.
Verborg Engineering B.V. Project example
Fully automatic steel drum leak tester. This leak tester can perform 2 different leak detection methods: Hard helium vacuum testing and pressure difference testing.
For tight head drums, the pressure hard helium vacuum testing method is used. This fully automatic system was able to reach a very high capacity this way. By using a standardised design, the project was easy to customize to the size of the used tight head drum. The amount it takes for the vacuum chamber to reach a pressure of 1mbar is only 2,3 seconds.