7 INCONDESCENT WELDERS, SPARK WELDERS AND ARC WELDERS; GUNS FOR PLASMA SPRAYING INCLUDING JETS, TIPS AND NOSE PIPES FOR USE IN CONJUNCTION THEREWITH; SAFETY HELMUTS FOR USE IN WELDING, BRAZING AND SOLDERING OPERATIONS; WELDING ELECTRODES, CONSUMABLE ELECTRODES; AND APPARATUS FOR USE IN WELDING, BRAZING AND SOLDERING OPERATIONS, NAMELY, ACETYLENE TORCHES, WELDING HEADS AND THERMAL SPRAY DIFFUSERS