Emissions from piping systems and associated equipment are a source of pollution and danger. Plant operators must take due care of the monitoring, reduction and possible elimination of such hazards. Descote bellows sealed globe valves isolate the service fluid inside the valve. A metal bellows, welded to the bonnet and the stem, provides a continuous and hermetic barrier between the media and the atmosphere. The other major potential leakage area of a valve, the body-bonnet connection, can be addressed by either special gaskets, double sealing or welded lips which provide continuity of the pressure envelope. Descote also provide special valve arrangements for extremely severe applications. In the case of critical fluids, such as phosgene, the only dependable option for emission control is “double containment” of the valve body, ensuring a “zero leakage/zero ppm” performance. Where constant monitoring is required to verify emission elimination, a leakage detector system can be added to monitor leakage between the bellows and secondary safety packing; between the flange double gaskets, etc. Various detection points can be linked together to allow efficient centralised monitoring of each valve.
