Pressure-loss measurements of fibre pulp at high consistency

Conventional paper and board manufacturing with forming consistencies over 4% is difficult or impossible because of the problems of web forming. The maximum consistencies of fibre suspensions that can be pumped with MC pumps are about 18-20%. Piston pumps with line pressures over 200 bars allow much denser fluids to be pumped. The key idea of forming with high-consistency pulp is energy savings at all stages of the processing, i.e., during refining, pumping and forming of the pulp, as well as during drying of the formed object. In this case, the formed object will not be paper; instead it may be thick board-like web. The web or object has to have some adequate strength properties, though there is less need for other normally important properties such as formation, brightness, printability, etc. of conventional papermaking.