High consistency pulp tower with a parting member and the introduction

Abstract

Cellulose pulp is discharged from the dilution zone of a high consistency pulp tower at a substantially even volume flow and a substantially steady pulp consistency by mounting a particular parting member within a bottom portion of the tower. The parting member is constructed so as to define a first cross-sectional area between it and the tower side wall which is smaller than a second cross-sectional area below the parting member, in the dilution zone. The parting member may comprise a cone, cone frustum, pyramid, or pyramid frustum mounted substantially concentrically with the tower axis. The first cross-sectional area is at most 95% of a second cross-sectional flow area in the dilution zone, and typically about 90% or less. A ring may extend inwardly from the side wall at the parting member and define the first cross-sectional flow area with the parting member. Alternatively the parting member may itself comprise a ring having a substantially triangular (e.g. equilateral triangle) cross-section with an upwardly pointing apex, the ring spaced from the side wall and substantially concentric with the tower axis. Pulp is diluted from a consistency over 20% to a consistency of about 3-15% in the dilution zone and discharged from the dilution zone. Two to six mixers may be provided in the dilution zone to facilitate pulp flow through the first cross-sectional area to the dilution zone, to effectively dilute the pulp in the dilution zone, and to discharge the diluted pulp through an outlet.