A Novel Fouling Monitor

A tapered tube device is described which allows the influence of a range of shear stresses on the formation of a wall fouling layer to be examined in the same experiment. The device is demonstrated for fouling from reconstituted skimmed milk over a range of surface shear stresses and temperatures. The shear stress required to maintain a clean surface, the critical shear stress, is shown to a function of temperature, with an activation energy of 150 ± 10Kj/mol. A mechanism for the early stages of fouling is proposed, based on a simple application of turbulent burst theory, which explains the form of the experimental results. The fouling from reconstituted skimmed milk is shown to be a two-stage process. Suggestions for the modelling of such processes are given. The further development of the tapered tube device is outlined.