Abstract: A conical grinding cutter for use in grinding, or refining, wood pulp, wherein the cutter part constituted by the mantle of the cone is assembled of a plurality of separate sectors. In order to improve the grinding cutter of prior art composed of sectors, in the present invention the cutter sectors have been welded together by their sides for achieving a rigid juncture substantially over the entire length of the grinding cutter.

Abstract: A procedure for controlling the surface mass distribution of a paper web being formed on a dry paper machine, wherein the suction air recirculated to the former is utilized. In procedures of prior art, the surface mass distribution has not been uniform enough. With the aid of the present invention the problem has been solved in that the quantity of air blown to the former is adjusted in the cross-machine direction in order to obtain the desired surface mass distribution.

Abstract: A cutter segment for a disc grinder or the like, said grinder consisting of two oppositely placed cutters made up of several segments attached to each other, at least one of the cutters being rotatable, said cutter segments being provided with a rough surface or with teeth and grooves for the grinding of material such as wood chips. With prior-art grinders of this kind, exhaustion of the steam produced in the grinding process has proved to be a difficult problem. The cutter segment of the invention solves this problem in that the segments of at least one of the cutters are provided with one or more exhaust channels having a sectional area essentially larger than that of the grooves.

Abstract: Procedure for preparing thermomechanical pulp from wood chips, wherein the chip flow is conducted from a storage reservoir under normal pressure through a first lock feeder into a pressurized steaming chamber, where the chips stay for a few minutes and are heated to an optimum temperature of 100.degree. to 125.degree. C., and from the steaming chamber through a second lock feeder to a feed means which supplies the chips into an enclosed hot refiner. In the procedure the steam discharging from the throat of the refiner against the chip flow is utilized for heating the chips in the steaming chamber, and the steam separated from the mechanical pulp is led off for use elsewhere.

Abstract: Continuously operating procedure for preparing hot groundwood from wood chips, wherein the chip flow is conducted into a pressurized steaming chamber, where the chips reside a few minutes and are heated to a temperature in excess of 100.degree. C, and from the steaming chamber to a sealing feeder, the rotor of which is circumferentially divided into mutually adjacent compartments, each of which in its turn fills through a feeding aperture with chips and empties in another angular position of the rotor through a discharge opening into a feeding conveyor, which carries the chips to a hot grinder, the groundwood derived from the latter being carried to further treatments, whereat the steam generated by the hot grinder and discharging from its throat in the direction against the chip flow is conducted away from the grinder. The steam is conducted through the feeding conveyor to the sealing feeder, where each compartment, as it is emptied of chips in its turn, fills with steam.