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J.F. Oliver and N. Wiseman. Significance of felt roughness in wet pressing. In Fibre-Water Interactions in Paper-Making, Trans. of the VIth Fund. Res. Symp. Oxford, 1977, (Fundamental Research Committee, ed.), pp 411–417, FRC, Manchester, 2018.


Several widely recognised operational problems in papermaking have been attributed to the felt structure. All of these result from phenomena occurring at the macroscopic level, e.g. shadow and yarn-marking.⁽¹⁾ However, phenomena occurring at the microscopic level, i.e. at the scale of the individual fibres of the felt and paper, have received less attention.

Recent experimental studies⁽²⁻³⁾ on press felts show that their surface properties strongly affect water removal in wet pressing. Two mechanisms have been proposed to account for these effects : rewetting, and load uniformity. While a first approach to a quantitative discussion of the effect of felt properties on rewetting has been made,⁽³⁾ account of the structural influence on load uniformity has hitherto been considered only from a qualitative standpoint.⁽²⁻⁴⁾ In this briefnote we present some findings of a more quantitative study⁽⁵⁾ to investigate the latter problem. In this study we have evaluated felt roughness and assessed its effect on water removal.

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