Bubble Pressure Tensiometers

The bubble pressure tensiometer is an instrument used for determining the dynamic surface tension of liquids and wetting characteristics of surface active liquids in cleaning baths.  A quick and flexible method, the bubble pressure tensiometer is used in quality control, research and development for characterisation of water-based solutions such as surfactants, polymers, acids and bases.

When measuring the surface tension in accordance with the bubble pressure method a capillary is dipped into the liquid and an air-current is directed into it. Through the increasing gas pressure, a gas bubble forms at the lower end of the capillary, the radius of which reduces permanently.  When the bubble radius equals that of the capillary, the gas bubble bursts and breaks away from the capillary.  At that moment the gas pressure reaches its maximum.  In accordance with the special form of the Laplace-relation, the maximal pressure and the surface tension correlate.

SITA tensiometers are easy to handle and functions are adjusted to their respective applications.  The measuring values of all SITA bubble pressure tensiometers,  DynoTester+, Pro Line T15 and the Science Line T100  are comparable to each other so measuring results achieved in research can be used for process monitoring.