This a non destructive testing process useful for checking leak tightness after electron beam welding or vacuum brazing.
The method can only be used on objects where the joint area can be sealed off and vacuumed down, the joint area can then have helium gas applied, any area that is not fully sealed will allow the gas to enter the object and pumped out via the sensor, the machine will indicate the leak and the severity.
Particularly useful for checking sensors and bellows that may be part of a line where leak tightness is essential.
The typical leak tightness is of the order 2x10-8 cc/hr
which could permeate through cast material.
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