CONTROLLING PARTICULATE MATERIAL

摘要

The movement of particles in a liquid flowing in a duct (2) is controlled by an ultrasonic standing wave having nodal fronts at a small angle to one pair of side walls of the duct. As the liquid flows along the duct, particles responsive to the acoustic energy are held on the oblique nodal fronts and are carried along these by the flow so that they also move towards one side wall (2a). Particles in the vicinity of that one side wall are swept from the nodal fronts by the liquid drag forces. At the duct exit the particles will therefore tend to be concentrated in that portion of the liquid flow that passes nearer said one wall (2a).