Pin detachment method

Measuring the force (the weight) needed to break away a body from the liquid surface is the basis for many variations of the detachment method. The body may be in the form of a rod with a circular base (Pin detachment method), a rod with a rectangular base (Wilhelmy slide method), a horizontal circular ring (Ring method), etc. The different forms of the detachment method have been used for surface tension measurement of liquids from room temperature up to approximately 1000°C. It is evident that the detachment methods can be used only in cases when the liquid wets the measuring body. 

Figure 6.9. The pin detachment method. 1 — the measuring body 2 — the circular base 3 — the liquid.

The mathematical analysis of the detachment of the circular (pin method) and rectangular (Wilhelmy method) rod from the liquid surface was given by Lillebuen (1970). He showed that the surface tension of the liquid is given by the equation... 

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