Helium spill testing uses a Helium Leak Detector, likewise alluded to as a Mass Spectrometer Leak Detector (MSLD), to track down a hole inside or outside of a framework and afterward measure the break rate. The helium spills in/out of the tried item and is estimated by the indicator. The identifier decides the hole rate because of the helium focus and stream rate.
A total Helium Leak Detector framework contains the accompanying components:
- Helium mass spectrometer to identify the mass of the helium
- Vacuum framework to keep up with adequately low strain for the spectrometer
- Valves that control individual strides of the estimating cycle: departure, testing, and venting
- Electronic estimating and control frameworks
- Power hotspots for individual parts – valves, circuits, and so forth
- Installations, which interface the tried item to the finder
Helium leak testing at Lower Limits
While testing at 1 x10-9 and underneath, one might have to do extra things to have the option to finish a practical test. One might have to cleanse away any sticking helium left in the part to be tried or the test chamber. For instance, with the chamber and part open to the climate before the test, they are presented to a helium convergence of 5 ppm. The helium can stick to different surfaces and influence the consequences of the test. In this way, one might have to “wash” away from any sticking helium in the chamber and part in a gas containing no helium.
Helium leak testing at high production rates
Whenever high volume creation requires a high vacuum, you should likewise consider the time brought to siphon down to the necessary degree of vacuum, this can be huge. At higher creation rates, having a lot more limited chance to test a section, huge leakers might be an issue. The flooding of the hole test instrument with helium might require a few minutes for the helium to diminish to a level where testing can recommence. To diminish the impact of a huge leaker one can; move toward the full test strain in stages, move toward the full fixation, flush the mass spec with gas with no helium present or pre-screen utilizing an air rot strategy before helium testing. Air rot pre-screening will permit known bigger holes to be eliminated preceding helium spill testing. While testing at rapid it is critical to diminish the test time to its base. To do this one might need to utilize various strategies to; decrease the test volume (by infilling voids and guaranteeing the least line run volumes), nitrogen flush, and so on Obviously fast the programmed treatment of the item and programmed association to have a huge influence.
Helium Bombing for testing hermetically sealed containers
While attempting to test airtight fixed holders, it would be great to attempt to embed some discernible helium in the get-together interaction before the last seal is made. On the off chance that presenting helium inside the part is absurd, one can attempt to drive helium into the gadget utilizing a method called bombarding. Helium bombarding is accomplished by constraining a break by compressing the gadget inside a helium gas chamber. Commonly, the chamber is first cleared to eliminate barometric strain air from round the parts and afterwards compressing with packaged expand gas. The gadget is then absorbed by the compressed helium to drive helium into the conceivably spilling part. Then, at that point, the chamber is then vented and the parts removed from the chamber. The parts are then tried with a blend of a gross hole test, to guarantee that there is not a major break, and afterward a high vacuum helium spill test in an encased chamber utilizing a helium mass spectrometer.
Tooling & Pipework
Assuming one is planning to helium spill test a section; it is vital to take note that the tooling and pipework used to make the test volume and helium gas supply should be released tight to a more significant level than the break test edge. This implies that cautious designing of the seals is essential, especially where convoluted seals are required, like right calculated seals for 2 opposite faces. One should likewise utilize helium release tight valves and pipework and give specific consideration to the measuring of the vacuum pipework.
Helium Mixing, Helium Re-use and Helium Recovery
The amount of helium might become huge while testing huge volumes, at higher tensions as well as at rapid. There are various strategies to lessen the utilization of helium gas. The first of these is to blend the helium in with another cheaper gas, either nitrogen or packed air. Here the awareness of the test isn't undermined by the blending system. The second of these is to re-utilize the helium from one test by extricating it from the gadget and afterwards driving it into the following gadget. This can frequently be carried out by a blend of a vacuum siphon and basic air chamber course of action if the volume isn't excessively huge. The convergence of the helium can be observed between cycles utilizing a mass spectrometer or another sensor. Assuming that the fixation falls under an adequate level, the helium should be taken out and another charge of helium is utilized. The third strategy is helium recuperation. The helium is removed into the middle of the road holding vessel to then be compacted back to high strain to recuperate the helium.
