Spray unit for cooling extruded sections

Abstract

The spray unit lies downstream, in-line with an extrusion press and serves to cool metallic sections in particular sections of aluminum or an aluminum alloy from all sides. The cooling medium emerges from spray nozzles program-controlled in the direction of the section. The distance, the cross-section distribution and the direction of the spray nozzles are adapted specific to the geometrical shape and distribution of mass in the section. The optimum parameters are determined and stored in the unit processor. The spray nozzles are arranged in nozzle beams running in the direction of the extruded section. The nozzle beams comprise at least one longitudinal water channel and two longitudinal air channels, whereby cross-intersecting channels branch off from the water channels to the spray nozzles and the air channels terminate in air gaps which are directed towards the nozzle outlets. The extruded sections are passed through the spray unit and cooled, at a rate that exceeds the critical cooling rate specific to the material, by a program-controlled, sprayed cooling medium in a manner that takes into account the shape of the section and the distribution of mass in the section. Using uniform cooling on all sides, sections that are extruded straight can be kept straight, while sections that are distorted on extrusion can be corrected with respect to bending and/or twisting by non-uniform cooling.