Neue Labormethode zur Beurteilung des Schaumverhaltens von Fluiden

In previous papers [1] a new laboratory method for the evaluation of air release behaviour of liquid lubricants has been described. A variant of that method can be applied to the evaluation of foaming behaviour. In order to conduct a foam measurement, a sample of the test fluid is filled into a thermostated cylindrical glass vessel. Using a laboratory stirrer synthetic air is dispersed in the sample. After stirring a surface foam layer comes into being at the top of the sample fluid. The height of the surface foam is measured visually as a function of air release time. With simplifying assumptions the results of the measurement make possible to characterize the foaming behaviour of the test fluid in a model sump. Fresh and aged transmission fluids as well as engine oils have been discriminated in accordance with practical experience.