Abstract: A disc filter assembly includes a number of filter discs mounted in a vat by a horizontal shaft with an inter-disc volume between the discs. A feed mechanism is provided that makes it possible to feed the pulp suspension onto the surface of the liquid, directed toward the most concentrated pulp in the vat, in such a manner that the feed is insensitive to fluctuations of the suspension surface level in the vat. This is accomplished by feeding the suspension into the vat interior directly into each of the inter-disc volumes, as by using a chute (which may have the approximate configuration of a hollow triangular parallelepiped) for each volume. A header for supplying pulp suspension to the chutes may be mounted on or spaced from the sidewall of the vat, or above the vat.

Abstract: A deaeration vessel has a partition wall dividing the hollow vessel body into first and second portions, and defining a weir with a top surface establishing the level of pulp suspension in the vessel body. Turbulence in the deaerated pulp is minimized by providing the outlet for deaerated pulp immediately adjacent the partition wall, in the bottom of the vessel body first portion (on the same side of the weir as the inlet conduits for the suspension being deaerated). The weir is preferably configured so that the top surface, defining the liquid level within the vessel, overlies the outlet. A partition wall may extend substantially linearly at an angle of about 60.degree. to the bottom of the vessel, or it may have a vertical bottom with a top extending at an angle to the bottom, or it may be continuously curved from the vessel bottom to the top surface, about a horizontal and/or vertical axis.