Vacuum leaks can be small holes in the system that permit gas to escape or enter unintentionally. They can be severe depending on their size, temperature, type of gas pumped through, and outside pressure differentials.
Vacuum Leak Testing Methods
There are four ways to detect vacuum leaks. These include bubble tests, pressure decay and pressure rise and helium tests. To know more about vacuum leak tests and vacuum seal testers, visit https://flexpakinc.com/product/.
The tester will place the leaking item under water and mark where bubbles are formed. You can also use detergent to mark the area where bubbles have formed.
Tests for Pressure Decay
The tester must evacuate a sealed vacuum vessel until a certain pressure is reached. After a specified time, the tester closes and reopens the inlet valve of the pump.
This is repeated several times by the tester to see how long it takes for vacuum to return back to its original level. A leak is most likely if the time remains constant. A decrease in time does not necessarily mean that there is no leak.
Pressure Rise Tests
The pressure rise test is basically the opposite of the pressure decay. The vacuum level is measured against the time it took to reach that level. The curve will become straighter if there is a leak.
The only way to detect a leak less than 1×10-6mbar *l/s is through helium testing. Because of its low mass, low cost and inertness, helium is used by testers as a tracer gas.