Bubble Pressure Method
The maximum bubble pressure method avoids error-causing effects by measuring surface tension within the body of the fluid. It is the "Simplest Accurate Method" for measuring surface tension.
Two glass probes having orifices of different diameters are positioned below the surface of the liquid. A pressurized process gas source forms bubbles in the liquid, and the differential pressure of the bubbles is measured and equated to the surface tension of the measured liquid. Unlike other maximum bubble pressure methods, the SensaDyne's patented double probe method allows complete independence of immersion depth, for accurate repeatable results.
The Tensiometer's pneumatic system provides constant volumetric gas flow, making the flow independent of down-stream pressure. Flow rate to each orifice is adjustable through external valves. This allows interface formation time (bubble rate) selection from up to forty or more bubbles per second to one bubble every two minutes. Bubble rate, surface age, fluid temperature and fluid surface tension are displayed on the computer's video terminal.