Abstract: A blade wheel for a centrifugal pump has at least two blade discs spaced along an axis of rotation of the discs. At least one row of generally radial blades extends between the blade discs and is spaced successively in a circumferential direction of the blade discs with blade ends radially outermost at peripheries of the blade discs. The blade ends are at an angle to the axis of the rotation of the discs, whereby each blade end has a leading edge and a trailing edge in the circumferential direction. In order to reduce pressure variations caused by the blades in a discharge conduit of the pump, the leading edge of the blade end of a trailing blade in the circumferential direction is one of in axial alignment with the trailing edge of the blade end of a successively leading blade in the circumferential direction and ahead of the trailing edge in the circumferential direction.

Abstract: A decker comprises a tank having a thickening drum mounted rotatably therein and including a filtering shell. The inside of the drum communicates with an inlet for feeding mass, whose consistency is to be increased during the thickening process and outlets for discharging the thickened mass after the thickening process. The filtrate separated from the mass being thickened, is arranged in a flow communication from the inside of the thickening drum through the filtering shell of the drum to the bottom portion of the tank. At least one separating member is placed in the bottom portion of the tank outside the drum and forms a partition point or partition line situated transversely with regard to the direction of rotation of the drum and at a predetermined, angular distance from the horizontal plane coinciding with the axis of rotation.

Abstract: A method of increasing the temperature of shower water used in a wood grinding process wherein wood is ground in a grinding space (3) under a pressure exceeding atmospheric pressure, and warm shower water (G) is fed into the grinding space for improving the grinding process. In order to compensate losses of shower water replacement water (E) is added to the shower water circulating system. The replacement water is fed into the groundwood pulp (A) after the grinding space but before a steam separator. Thus cooler replacement water can be heated by the heat energy otherwise released from the groundwood pulp in the steam separator, and the temperature of the shower water can be maintained close to 100.degree. C. in spite of the addition of cool replacement water and without using a pressurized steam separator.