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Abstract

An extinguishing barrier comprises an optical flame sensor and a HRD-Suppressor located downstream of the detected flame front. The effectiveness of an extinguishing barrier is based on its ability to detect an explosion in a pipeline by means of an optical flame detector whose tripping signal is amplified and then very quickly actuates the detonator-actuated valves of the pressurized HRD-Suppressors.

Extensive practice-related tests in pipelines, having different cross sections and length, in pipelines connected with different vessels, have shown that extinguishing barriers can be used without reservation to halt or stop an explosion in practice. The amount of suppressant agent required depends on the nature of the combustible dusts, the nominal diameter of the protected pipeline, the explosion velocity and the maximum reduced explosion overpressure in the vessel. Most significantly, the theoretical understanding of explosion propagation and extinguishing has led to computer design guidance which has simplified system design. Explosions can be combated effectively in pipelines up to diameter 2500 mm.