Patent ID: 7240863

Claim:
A method of refining wood pulp comprising: a) providing a conical pulp refiner comprising a refiner housing having a pulp inlet and a pulp outlet with a refining zone therebetween, said refining zone comprising a flat, upstream refining zone and a conical, downstream refining zone, b) feeding pulp through said pulp refiner from said pulp inlet to said pulp outlet at a selected production rate, and refining the pulp in said refining zone with discharge of refined pulp of a target consistency at said pulp outlet, c) adding a first controlled amount of dilution water to said pulp upstream of said conical refining zone, in response to loss of water in said pulp, to establish a pulp consistency effective to maintain an acceptable refining intensity for refined pulp quality, relative to said production rate in said refining zone, and d) adding a second controlled amount of dilution water to said conical refining zone, to maintain said target pulp consistency at said pulp outlet; wherein said pulp consistency in step (c) is controlled by said first controlled amount of dilution water, independently of said target pulp consistency in step (d) controlled by said second controlled amount of dilution water.