Abstract: The washer comprises an open-topped vessel having a tube mounted vertically and centrally therein. Post-primary bitumen froth is fed to the upper end of the tube. Pairs of down throw and up throw propellers mounted to rotate in the tube act to shear the froth as it passes down through the tube. At its lower end, the tube is closed off by a transverse wall. Slots are formed in the tube side wall to provide an exit. The sheared mixture thus changes direction as it leaves the tube. In the vessel chamber, solids and water sink downwardly and are removed as tailings through a bottom outlet. The sheared aerated bitumen rises and forms a new forth that is recovered in a launder. Middlings are withdrawn from the chamber and recycled to join the feed. The product froth is reduced in water and solids relative to the feed froth.