Abstract: A method and a measuring arrangement for monitoring the condition of a grinder stone of a pulp grinder. A temperature profile for a grinding surface of the grinder stone is determined substantially along the entire length of the grinder stone, a variable representing at least one piece of temperature data of the grinding surface of the grinder stone is determined on the basis of said temperature profile, and the variable representing said temperature data is compared with a reference variable corresponding to said temperature data. If this variable differs from the reference variable in a predefined manner, the state relating to the condition of the grinder stone is identified as abnormal.

Abstract: A method and a measuring arrangement for monitoring the condition of a grinder stone of a pulp grinder. A temperature profile for a grinding surface of the grinder stone is determined substantially along the entire length of the grinder stone, a variable representing at least one piece of temperature data of the grinding surface of the grinder stone is determined on the basis of said temperature profile, and the variable representing said temperature data is compared with a reference variable corresponding to said temperature data. If this variable differs from the reference variable in a predefined manner, the state relating to the condition of the grinder stone is identified as abnormal.

Abstract: The invention relates to a method for controlling a multi-step screening apparatus (1), the method comprising controlling other accept, reject and dilution flows in relation to the flow measured in the accept channel (7a) of the first screening step (3a). Thus a simpler control unit (9) can be used and accept of higher quality can be obtained than before. The invention further relates to an apparatus for controlling a multi-step screening apparatus (1), said apparatus comprising a control unit (9) arranged to measure the flows of all accept, reject and dilution water channels (7a-7c, 5a, 5b, 11a, 11b) and to adjust the flow of the other channels on the basis of the flow of the accept channel of the first step.

Abstract: In the arrangement, the cross section of a blade rotating close to the surface of a screen cylinder changes in such a way that as the pulp consistency changes in the vertical direction of the screen cylinder, the cross section of the blade also changes in order to operate as efficiently as possible according to the pulp consistency by the blade.

Abstract: A method and apparatus for controlling a multi-step screening apparatus (1) controls other accept, reject and dilution flows in relation to the flow measured in the accept channel (7a) of the first screening step (3a). Thus a simpler control unit (9) can be used and accept of higher quality can be obtained than before. The apparatus has a control unit (9) aranged to measure the flows of all accept, reject and dilution water channels (7a-7c, 5a, 5b, 11a, 11b) and to adjust the flow of the other channels on the basis of the flow of the accept channel of the first step.

Abstract: A method and an apparatus for sharpening the surface of a grindstone for a pulp grinder. In the method a high-pressure water jet is obliquely projected on the surface of the grindstone for detaching bonding material between abrasive grains, without excessively wearing a medium between grinding segments.The apparatus comprises a nozzle, arranged to spray water obliquely onto the surface of the grindstone and a high-pressure pump for feeding high-pressure water through the nozzle. The nozzle is arranged to be moved by transfer means in the axial direction of the grindstone while the grindstone is being rotated.