Purging and pressurizing systems is one of the most versatile explosion protection methods. These Systems are based on the principle that in Zone 1 or 2 the gas mixture in the ambient atmosphere, which may ignite under certain circumstances, is removed from the housing by an initial Purge process. After the purge phase, sufficient compressed air or inert gas is supplied to compensate for leaks from the enclosure. This permanent overpressure, achieved using compressed air or inert gas, prevents any potentially explosive atmosphere in the ambient air from entering the enclosure.
During the rapid exchange purge phase, an internal pressure of approximately 3.5 – 12 mbar (1.3” to 5.0” Water Column) is achieved. During operation, this internal pressure reaches 0.6 – 3 mbar (0.3 to 1.2” Water Column).
The pressurizing system is particularly suitable for installed equipment which is not approved for use in hazardous areas. Once installed in a purge panel, it can then be used directly in the hazardous area.