Description AL-KO AFU-ECO is a welding fume extraction system with integrated heat recovery for parallel welding fume extraction at several workstations. The modular system is divided into two functional levels. Level 1: Extraction unit consisting of pre-separation chamber, filter chamber, compressed-air cleaning, and clean-air fan. Level 2: Integrated fresh air supply area consisting of suction chamber, filter chamber, and fan. Connected by a plate heat exchanger, which allows up to 67 % heat recovery efficiency.