Bubble Test

Recognizing the environmental legislation and Health and Safety issues in using solvents such as Isopropanol (IPA) as the test liquid, B&M Longworth has developed a process where deionized water and a surfactant are used as the testing medium.

The filter (candle or disc) is submerged to a predetermined depth in the test liquid; air is introduced into the core of the filter with the pressure gradually increasing. The test liquid pushes through the filtering medium surface at a position on the filter body in line with the largest pore size or notable hole. The pressure at which air bubbles are emitted from the surface relates directly to the bubble-point pressure.

The bubble test is a method of assessing the structural integrity of the filter element. The bubble point value is proportional to the size of the largest hole present in the media, which is an essential factor in assessing the integrity of the filter element.

Example of a bubble point test

The bubble test is reliable and relatively simple to carry out. It provides a visual indication of where any defaults are.