Patent ID: 7169021

Claim:
A method for controlling a water jet sharpening sequence of a pulpstone in at least one of a piston-loaded pulp grinder and a chain-feed pulp grinder, wherein at least one sharpening water jet of a water sharpening apparatus, arranged with respect to the pulp grinder, is directed toward a surface of the pulpstone, the at least one sharpening water jet having a treatment pressure capable of detaching material from at least a portion of the surface of the pulpstone, whereby the surface of the pulpstone is treated over the width thereof as the pulpstone is rotated, said method comprising: determining an actual quality value of at least one variable of a fiber pulp ground by the at least one of the piston-loaded pulp grinder and the chain-feed pulp grinder; defining a target quality value for each of the at least one variable; directing the actual quality value and the corresponding target quality value to a control unit of the water sharpening apparatus, the control unit being configured to be responsive thereto so as to provide an adjustment strategy, including a control range, for controlling the water jet sharpening sequence; controlling the treatment pressure of the sharpening water jet relative to an error value between the target quality value and the corresponding actual quality value of the fiber pulp; and controlling a treatment interval to maintain the treatment pressure within the control range in accordance with the adjustment strategy.