PurgingNitrogen purging is an industry standard technique for the replacement of a hazardous or undesirable atmosphere with an inert dry atmosphere. Nitrogen can be used for a range of similar applications such as line or tank purging, drying, line clearing, pigging or pressure transferring. Below are some examples of purging systems.
Pressure-hold-vacuum methodThis method is commonly used when the vessel being purged only has one opening or in batch operations like purging ethylene oxide sterilizers. Nitrogen is used to pressurize a vessel or line, it mixes with and dilutes the contents and then the diluted mixture is vented to emission control units. This process is repeated until the vessel is sufficiently purged. The ending concentration for each cycle is proportional to the starting concentration and the high and low pressure in the cycle.