Helium Leak Testing: Spray Probe
When using the spray probe technique for a helium leak test inspection, the leak detector is hooked directly to the system under test and the inside of the system is evacuated. Once an acceptable vacuum is achieved, helium is sprayed discreetly on the outside of the system, with particular attention being paid to any suspect locations. Any leaks in the system, including defective welds (caused by cracks, pin holes, incomplete welds, porosity, etc.), flawed or missing gaskets, leaks due to loose clamps, or any other defect will allow helium to pass and be readily detected by the machine. The source of any leaks can then be accurately pinpointed and repaired.
The spray probe process is used to achieve the highest level of sensitivity. The equipment being used dictates the maximum sensitivity achievable; in Jurva Leak Testing’s case it is 2x10-10 std cc/sec. This technique requires that the system being tested is relatively leak tight prior to testing, as an ample vacuum is required for testing. However, by using special throttling devices a gross test can typically be performed. The gross test should eliminate any major leaks, permitting the use of increased sensitivity.
Examples of systems we test using the spray probe technique:
- A-bar furnaces
- E-beam systems
- Laser systems
- Metal deposition equipment
- Distillation systems
- Vacuum systems