Fume extraction torch for GMA Welding: a new repository for improving the efficiency of such torches

The high deposition rates and high temperatures implemented in semi-automatic welding lead to high fume emissions. Such emissions being classified as Group 2B, "possibly carcinogenic" by the IARC, prompts implementation of local collection systems. The fume extraction torch, in which suction is integrated into the tool, is the most attractive solution, but its capture efficiency is often disappointing in practice. The main parameters affecting fume capture efficiency were studied (extracted flow rate, positions of suction openings, torch angle of inclination, deposition rate, etc.). These results provide guidance in fume extraction torch design and data for setting resource objectives. The theoretical velocity induced by suction is estimated from the extracted flow rate and the suction opening position; it is the main design parameter and its value should never be less than 0.25 m/s.