Preventing condensation from affecting electro-optic equipment is a crucial task, not only to maintain its performance in the field, but also to prevent corrosion. Traditionally this is accomplished using a two-point nitrogen purging system, but this has its drawbacks. Firstly, the nitrogen follows the quickest path from entry port to exit, leaving residues of undried air in corners of the system.
Secondly, the system often does not purge to the required dewpoint, because trapped undried air releases moisture back into the system. To overcome these problems, Stream Peak International of Singapore (Hall A, Stand 237) has devised a single-point purging system known as NEPS (nitrogen environment purging system). By using a single-point system, NEPS creates an internal pressure so that the nitrogen circulates properly to flush out all moisture. Moreover, the system provides a more accurate dewpoint reading, as this does not increase significantly after purging.
NEPS is available in a number of forms, including rack-mounted systems for laboratory use and a portable version for mobile use. The system automatically shuts off when purging is complete, allowing technicians to leave the system running after the desired pressure level and dewpoint have been set. The system has been shown to save significantly on the amount of nitrogen used, and purging time can be greatly reduced. A typical process that would take several hours with a two-point system can be undertaken in around 45 minutes with NEPS.