backflash

Backflash refers to a sudden, uncontrolled reversal of flame into a gas supply line or torch, often accompanied by a distinctive popping or hissing sound. This phenomenon occurs when the flame front propagates back through the torch nozzle and into the gas mixture, potentially causing damage to equipment or posing a safety hazard. Backflash is typically caused by a combination of factors including improper gas pressures, a worn or damaged torch tip, insufficient shielding gas flow in welding applications, or the presence of contaminants in the gas lines.

The danger of backflash lies in its ability to extinguish the intended flame and create an explosive mixture of fuel and air within the supply system. This can lead to a flashback arrestor, a safety device designed to prevent the propagation of flame, being activated. Flashback arrestors work by rapidly cooling the flame front, thereby stopping its passage. Regular maintenance of welding and cutting equipment, adherence to correct operating procedures, and ensuring proper gas flow rates are crucial in preventing backflash. Diagnosis of the issue often involves checking equipment for damage and verifying correct pressure settings.