A spiral conveyor construction comprises an endless conveyor belt guided on a conveying path. At least a part of the conveying path surrounds a drive tower. Spaced along the periphery of the drive tower are arranged vertical engagement members. Additionally on a lower section of the drive tower adjacent blocks are provided, radially projecting further from the drive tower than the engagement members, and where the blocks are provided with a radially extending secondary rib.

The invention relates to a spiral conveyor construction comprising an endless conveyor belt assembled from a plurality of substantially identical modular belt links, where the endless conveyor belt is guided on a conveying path, where at least a part of the conveying path is surrounding a drive tower, where the drive tower can rotate around a vertical axis, such that the drive tower engages a side surface of the endless conveyor belt thereby propelling the endless conveyor along the conveying path characterized in that spaced along the periphery of the drive tower are arranged vertical engagement members, where at least some of these engagement members has a vertically arranged rib projecting radially away from the drive tower, and where on a lower section of the drive tower adjacent at least some of the engagement members with projecting ribs, blocks are provided, said blocks near the bottom of the drive tower radially project further from the drive tower that the engagement members, and where the blocks are provided with a radially extending secondary rib which secondary ribs extend from the block and increases their extend upwards from zero extend to an extend corresponding to the radially extend of the rib on the adjacent engagement member near the upper end of the block, and where the secondary ribs and/or the ribs on the engagement members engages and propels the endless conveyor belt along the conveying path.