For weighing method based surface tensiometer around world, you always can find two or more different specifications for travel ranges of lift stage, for example, travel range of KINO’s surface tensiometer is 50mm (with resolution of 0.007um), while that of Others’ may be 110mm (with resolution of 0.1 um). So, what is the difference between these two specifications?
(1) The resolution and accuracy has vital meaning in surface tension measurement.
For the reason of buoyancy existing, the height of liquid lamella pulled up by plate should be used to calculate the buoyancy. So, high accuracy and resolution of lift stage will be an important spec for surface tensiometer.
(2) Why does others’ surface tensiometer need larger travel range?
As its connecting method of surface tensiometer made by other manufacturers (such as Kruss or Dataphysics) is fixed method, while height of the probe for measurement of surface tension/contact angle usually varies so much, in which situation, larger travel range such as 110mm must be adopted. In contrast, USA KINO and some other manufacturers, say, Kyowa, use flexible connecting method, using extended connecting rod after test probe has been changed, hence larger travel range is not necessary herein.
In short, travel range of lift stage is not a spec to feature surface tensiometer, and it just depends on connecting method of probe and balance used by manufacturers.
(3)When travel range makes sense and is meaningful?
Usually, travel range becomes a vital spec when immersed depth controlling is needed for measuring dynamic contact angle and surface/interfacial tension based on DuNouy ring method, as well as for measurement of Wilhelmy plate method based surface/interfacial tension using zero buoyancy method, such as Kruss, where plate needs to be immersed and withdrawn about 2mm, and the immersed depth range is 0-40mm as described in the manual of their tensiomete r(page 67). And experimental results show that 50mm is enough for this situation.

So, in conclusion, the proper travel range is about 50mm, and larger travel range is not necessary for measuring surface/interfacial tension.