The development of a new method of fibre separation

摘要

Conventional basket pressure screens use holes, slots, and contoured screen plates together with a rotor to stimulate non-steady state motion and achieve optimum fibre separation. Orifice size, shape and type are selected on the basis of the desired separation, fractionation or throughput. Although satisfactory in many operations there is a real need to improve and extend separating options. A new method of fibre separation is proposed that employs the metal between the holes rather than the holes themselves. It is based on the fibre stapling. The results of a preliminary investigation are described in this paper. Three different designs of laboratory apparatus are described. One uses stationary, parallel wires with the suspension being poured manually along the wires. The second uses a series of rotating, equally-spaced, discs mounted coaxially on a shaft onto which the suspension is pumped as a jet directed at the disc edges. The third is similar in design to the second, but uses a single rotating disc. Data are presented to demonstrate the effect of various design factors such as metal thickness and relative jet to 'wire' speed-differential affecting fibre retention. The results are compared at various flow rates, fibre concentrations, and with various types of fibre. Fibre length, coarseness, freeness, and fibre length data are reported. The findings show that this method has merit over conventional screening in that wider length, coarseness and fibre length differences can be obtained under certain experimental conditions.