The objectives of this article are:
– First, to theoretically propose a uniﬁed concept: the net normal force per crossing point,
– Second, to experimentally undertake reﬁning trials on a pilot disc reﬁner in order to compare all concepts for the reﬁning intensity and to validate the chosen one.
We will begin by re-visiting the old concepts of the reﬁning intensity, in the low consistency regime. After a theoretical proof based upon the physics of the phenomena, applied to beaters and industrial reﬁners, a uniﬁed concept of the reﬁning intensity is proposed and strengthened: the net normal force per crossing point.
Then, experimentations are undertaken on a pilot reﬁner (single disc) in hydracycle (or batch) conditions. More precisely, the effects of the grinding codes and of the average crossing angle of the bars are analyzed in a set of 6 reﬁning trials. For these experimentations, different engineering concepts of the reﬁning intensity are compared (speciﬁc edge load Bs, speciﬁc surface load SSL, modiﬁed edge load MEL, net tangential force per crossing point and net normal force per crossing point). These reﬁning intensities should allow to analysing the cutting kinetics of ﬁbres.
All the chosen engineering concepts reach this goal more or less however the net normal force per crossing point is the best tool. Indeed, through the range of the data concerned, it revealed a clear monotonous evolution with the cutting kinetics on ﬁbres. The more is the net normal force per crossing point, the more is the cutting effect on ﬁbres.