What can be done if none of the safety devices available on the market are big enough to protect a gas system from accidents? The manufacturer Witt-Gasetechnik has found an impressive solution with its new Safety Group 645.
The solution combines several individual safety devices and switches them in parallel. “The approach sounds simple,” states Product Manager Andreas Heyer. “Yet the utmost expertise was needed to realise this.” A system is now available with the “645”, which can reliably protect large gas supplies, such as within thermal processing plants. There have been only few options for this until now.
Two, four or five safety devices can be combined on parallel in the fitting and up to 1,800 Nm³/h (63,536 SCFH) flow and 10-bar (145 PSI) maximum operating overpressure form the upper limits, depending on the gas type. The safety group is connected per flange (DN32-65) or internal thread on both sides (G, NPT, Rc). No matter whether town, piped or natural gas, acetylene, propane, hydrogen, ethylene or oxygen - the safety devices, such as the Witt model 85-30, protect against the hazards of uncontrolled gas mixtures. These can arise rapidly, for example, due to damaged nozzles, poorly screwed inserts or oxygen overpressure. “If a flashback occurs, the fire will travel through the line at twice the speed of sound,” warns Heyer. “Manual intervention is impossible.”
Safety devices could prevent the catastrophe. Three protection elements are integrated in the systems available from Witt: a gas non-return valve, a flame arrestor and a temperature-sensitive cut-off valve. Together they prevent flashbacks and explosive mixtures from forming. Thanks to its range of mixing, metering and control systems, combined with extensive safety technology and analysis instruments for all standard gases, Witt is regarded as one of the world’s leading manufacturers.