Impregnation procedure for a textile sheet

A process for continuously treating unbleached fibers comprising opening and mechanically cleaning said fibers;

• forming a sheet with said fibers and placing said sheet on a liquid-permeable endless moving belt;
• impregnating said sheet on said belt with a boiling-out solution;
• subjecting said sheet to boiling-out;
• rinsing said sheet and extracting liquid from said sheet;
• impregnating said sheet with a bleaching solution;
• bleaching said sheet;
• rinsing said sheet and extracting liquid from said sheet;
• and drying said sheet;
• wherein the impregnating of said sheet in one or both of said impregnating with said boiling-out solution and impregnating with said bleaching solution is carried out absent Use of mechanical roller means by impregnating the sheet with said boiling-out solution or bleaching solution by gravity feed of the solution in the form of a liquid curtain which is transverse to the direction of advance of the sheet on said belt and passing the belt holding the sheet over a suction means which provides a pressure drop to cause at least a part of the solution to pass into the sheet in a homogeneous manner, the rate at which the liquid is poured onto said sheet exceeding a threshold amount which is between 300%-1500% and the rate of liquid entrainment in said sheet during impregnation of said sheet being dependent on said pressure drop and independent of the amount of liquid poured and is controlled absent use of mechanical roller means so that the rate of entrainment is between 40%-400%, thereby providing a homogeneous impregnation of the sheet.