Abstract: A refiner (1, 2, 3) for refining fibrous material. And a blade element (18) for a refiner (1, 2, 3) intended for refining fibrous material. The blade element (18) having a refining surface (18?), which has blade bars (21, 23) and blade grooves (22, 24) between them. The top surface of at least one blade bar (21, 23) is provided with refining grits (25). The blade element (18) has portions (29, 30) forming a protruding part extending away above the refining surface (26a, 26b) and above the blade bars (21, 23) or the refining grits (25) on the refining surface.

Abstract: A refiner (1, 2, 3) for refining fibrous material. And a blade element (18) for a refiner (1, 2, 3) intended for refining fibrous material. The blade element (18) comprises a refining surface (18?), which comprises blade bars (21, 23) and blade grooves (22, 24) between them. The top surface of at least one blade bar (21, 23) is provided with refining grits (25). The blade element (18) has portions (29, 30) forming a protruding part extending away above the refining surface (26a, 26b) and above the blade bars (21, 23) or the refining grits (25) on the refining surface.

Abstract: A device for mechanical defibration of wood comprises a defibration surface for processing of wood raw material and loosening of fibers, said defibration surface comprising grinding grits fastened on a metal base surface. The grits (1) fastened on the metal base surface (2) are positioned within a determined distance from each other on the base surface, so that they form a regular defibration surface.

Abstract: The present invention provides a novel method and apparatus for producing pulp from lignocellulosic raw material, such as wood or annual or perennial plants, by mechanical defibration. According to the invention, fibers are peeled from the wood by means of grinding grits arranged on a defibration surface, wherein at least 90% of the protrusion difference distribution between adjacent or neighboring grits on the surface belongs to a value region maximally as wide as the average grit diameter. By means of the invention, a reduction in specific energy consumption of up to 50% or even more can be obtained.

Abstract: A device for mechanical defibration of wood comprises a defibration surface for processing of wood raw material and loosening of fibers, said defibration surface comprising grinding grits fastened on a metal base surface. The grits (1) fastened on the metal base surface (2) are positioned within a determined distance from each other on the base surface, so that they form a regular defibration surface.

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 for controlling the water jet sharpening sequence of a pulp grinder is provided, wherein a high-pressure sharpening water jet is directed toward a surface of a pulpstone with a water sharpening apparatus. An actual quality value of the fiber pulp is determined for at least one variable, and a target quality value is defined for each of the at least one variable. The actual quality values and corresponding target quality values are transmitted to a control unit that includes an adjustment strategy set for controlling water sharpening of the pulpstone. According to the adjustment strategy, the treatment pressure and/or the treatment interval of the sharpening water jet is controlled relative to an error value between the target quality value and the actual quality value of the fiber pulp. An associated apparatus is also provided.

Abstract: The present invention provides a novel method and apparatus for producing pulp from lignocellulosic raw material, such as wood or annual or perennial plants, by mechanical defibration. According to the invention, fibers are peeled from the wood by means of grinding grits arranged on a defibration surface, wherein at least 90% of the protrusion difference distribution between adjacent or neighboring grits on the surface belongs to a value region maximally as wide as the average grit diameter. By means of the invention, a reduction in specific energy consumption of up to 50% or even more can be obtained.

Abstract: The invention relates to a grinding segment comprising a ceramic part manufactured of grinding ceramic material and provided with a fastening hole, through which the grinding segment is attached to a frame of a grinder stone by means of a fastening bolt. A fastening sleeve is arranged in the fastening hole, and the fastening bolt is supplied through the sleeve. The fastening sleeve is pressed against the frame of the grinder stone due to the fastening force. A space filled with bonding agent is formed between the ceramic part of the fastening sleeve to join them together. The invention further relates to a grinder stone comprising a cylindrical frame and grinding segments according to the invention.

Abstract: The invention relates to a grinding element, which comprises a substantially planar fastening frame, and where two or more grinding segments made of grinding ceramic material are fastened to the outer surface of the frame by means of bonding agent. The fastening frame preferably comprises at least one fastening hole, and a fastening bolt is supplied through the hole to fasten the grinding element to the frame of the grinder stone. The invention further relates to a grinder stone, where a grinding surface is formed by arranging a required number of grinding elements according to the invention on the outer circumference of the stone's frame.

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 for controlling the water jet sharpening sequence of a pulp grinder is provided, wherein a high-pressure sharpening water jet is directed toward a surface of a pulpstone with a water sharpening apparatus. An actual quality value of the fiber pulp is determined for at least one variable, and a target quality value is defined for each of the at least one variable. The actual quality values and corresponding target quality values are transmitted to a control unit that includes an adjustment strategy set for controlling water sharpening of the pulpstone. According to the adjustment strategy, the treatment pressure and/or the treatment interval of the sharpening water jet is controlled relative to an error value between the target quality value and the actual quality value of the fiber pulp. An associated apparatus is also provided.

Abstract: The invention relates to a grinding element, which comprises a substantially planar fastening frame, and where two or more grinding segments made of grinding ceramic material are fastened to the outer surface of the frame by means of bonding agent. The fastening frame preferably comprises at least one fastening hole, and a fastening bolt is supplied through the hole to fasten the grinding element to the frame of the grinder stone. The invention further relates to a grinder stone, where a grinding surface is formed by arranging a required number of grinding elements according to the invention on the outer circumference of the stone's frame.

Abstract: The invention relates to a grinding segment comprising a ceramic part (11) manufactured of grinding ceramic material and provided with a fastening hole (12), through which the grinding segment (10) is attached to a frame (9) of a grinder stone by means of a fastening bolt. A fastening sleeve (14) is arranged in the fastening hole, and the fastening bolt is supplied through the sleeve. The fastening sleeve is pressed against the frame of the grinder stone due to the fastening force. A space filled with bonding agent is formed between the ceramic part and the fastening sleeve to join them together. The invention further relates to a grinder stone comprising a cylindrical frame (9) and grinding segments (10) according to the invention.

Abstract: An arrangement in a pulp grinder comprising a grindstone (1), a feed chute (2), and a piston to feed wood (3) against the grindstone (1). The arrangement comprises separate pushing members (6), which are arranged to push the wood (3) against the grindstone (1) at essentially the entire width of the feed chute when the percussion piston is moved back to the stroke position to allow the feed of a new batch of wood.

Abstract: An arrangement for providing continuous grinding in a pulp grinder comprising a feed chute and a piston in the feed chute moving lengthwise of the feed chute for pressing the wood in the feed chute against a grindstone. The arrangement comprises rotary feed members between the piston and the grindstone on the sides of the feed chute for pushing the compressed wood further against the grindstone. Also, the arrangement comprises a closing member that can be pushed between the compressed wood and the piston to prevent the wood from moving backward with the piston as the piston is moved to the initial position, ready for the stroke, to allow the feed of a new batch of wood.

Abstract: An arrangement in a pulp grinder comprising a grindstone, a feed chute extending to the grindstone, a piston moving in the feed chute, an auxiliary piston and closing members. In the arrangement, there are recesses on the front of the piston and apertures in the auxiliary piston so that the closing members can be pushed from both sides of the feed chute through the auxiliary piston to the recesses of the piston so that they settle behind the wood pressed by the piston.

Abstract: A method and an arrangement for treatment of reject material separated at screening of fibre pulp prepared by grinding wood. In the method reject material is fed against the surface of a grindstone (3) of a pressure grinder immediately before a normal grinding zone (6). The arrangement comprises a reject feeding equipment (12) placed immediately before the normal grinding zone (6) through which the reject material is fed to be ground again.