What is Bubble Testing? It is a simple, widely used qualitative method for proof testing and for finding defects or gross leaks in many different components. Two common forms of bubble testing are the direct-pressure method and the vacuum-box technique:
  • The pressurized method (the most common bubble testing method) is conducted by pressurizing a component with a gas and then either submerging it in a solution or applying a solution to the outside of the component. If a leak is present, bubbles will form on the surface because of the leak passing through the solution.
  • The vacuum-box method is conducted on parts that cannot be directly pressurized or where access is not available to both sides of a component. The test is conducted by applying a solution to an area of a pressure-boundary surface and creating a different pressure across the area, causing the formation of bubbles as leakage gas, such as atmospheric air, passes through the solution.
While helium mass spectrometer leak testing remains the gold standard for leak testing, sometimes bubble testing is the better choice. Helium leak testing is limited to 1 atm pressure differential while pressure test is only limited by the equipment capability. If you need to prove a design will work at 11,000 psi pressure bubble testing is the best way to do this. For parts that are used in high pressure applications RHSeals prefers to test 100% of these parts at a pressure above their usage pressure. PROS:
  1. Lower cost.
  2. No expensive equipment needed.
  3. Good for proof testing or quality checking high pressure assemblies.
CONS:
  1. Failure can be catastrophic for the assembly.
  2. Leaks on complicated assemblies can be missed.
  3. Very fine leaks can’t be found.
EVERY seal produced by RHSeals is electrically tested with a computer controlled hi-pot machine and leak tested using a helium mass spectrometer and/or a high pressure bubble test before shipment. Certification of tests are included with each shipment. RHSeals also has the capability to thermal cycle assemblies while under pressure to prove out designs. This quality process is one of the reasons why a Limited Lifetime Warranty is provided on all physical goods purchased from RHSeals.