Vibrating spiral conveyors are increasingly used in mechanical and thermal processes to convey bulk material upwards on an inclined plane by means of microscopic throwing movements. In contrast with linear vibrating conveyors, the path of a spiral conveyor is not straight but helical. Torsional vibrations are accordingly produced about the center axis of the spiral tower at a defined slope angle. These cause the load to be moved spirally upwards. Whereas with linear vibrating conveyors, the acceleration acting on the product is normally identical at every point on the conveyor deck, the magnitude of the acceleration of a spiral conveyor varies proportionally to the path radius. The operating conditions are therefore crucially influenced by the conveying conditions at the inner radius of the spiral path, in other words in the zone with the greatest inclination and the least acceleration.