Monitors purge vent gas
November 1st 2005 Emptying hydrocarbon storage tanks, reactors, pipelines or other vessels is dangerous because there is a high risk of creating an explosive mixture if purging is not managed correctly.
Vessels have to be purged with nitrogen to reduce the hydrocarbon content to below the lower explosive limit (LEL) before air can be allowed into the enclosure.
Infrared technology in Crowcon’s Triple Plus+ IR can be used to measure hydrocarbons at this low level.
With Triple Plus+ IR, the purge vent gas is monitored to determine when there is less than 100% LEL equivalent flammable gas concentration. An advantage of using a monitor rather than an estimated time-lapse is that the costly nitrogen purging can be stopped as soon as it is safe, with no need to guess the time or to run the purge longer than necessary.
The dual range IR sensor is scaled with both 0 to 100% volume and 0 to 100% LEL ranges, with an automatic range switch between the two. More articles from Crowcon Detection Instruments Ltd: | 
