A combination of a gas filter, non-return valve and flashback arrestor from Witt Gas Techniques Ltd can help protect steelworks from production failures during the refining process.

During refining oxygen and natural gas are mixed to supply a highly flammable mixture to the burner. Reverse gas flows and flashbacks are a real concern, and if they should occur, they can lead to the shut down of production. Until now the only safety devices available were non-return valves, which are not sufficient to deal with flashbacks.

The new solution from the Warrington, UK based gas safety, control, mixing and analysis equipment comprises a Gas Filter 625, to reduce contamination using nickel chromium steel filter inserts and a Gas Non-return Valve 339 with test ports to prevent the formation of explosive mixtures in the pipeline. Finally, the equipment boasts a parallel connection of five Flashback Arrestors 623 to guarantee the required high gas flow and stop flashbacks in the pipeline. A useful labour-saving feature of this solution is that due to the test ports on the 339 using non return valves, they do not need dismantling during annual inspections.

A steelworks, which recently had Witt Gas equipment installed has a natural gas flow of 350m/h and a low gas pressure of 3 bar, and all devices installed require a minimum pressure loss. A high capacity gas filter, a non-return valve and a parallel connection of 5 flashback arrestors were used. The total pressure loss was around 500mbar.