| abstract |
Improvements are afforded in method and apparatus for making non-woven fibrous webs including paper from a foamed aqueous furnish containing a surfactant in that the foam acquires and has imparted thereto physical characteristics as regards attainment of such a highly emulsified state that the bubbles are scarcely visible to the naked eye, as regards viscosity build-up of the foam to at least 22 seconds as measured with a Ford Cup Type B-4 and as regards the specific gravity being no greater than 0.35. Other improvements pertain to vortical mixing in the production of the foam, to combining the method and apparatus with conventional methods and apparatus and to handling the surfactant-containing water when in the foamed furnish and likewise as drained from the formed web. |