Vapor pressure curve for nitrogen Photo 1. When using a contacting seal, a temperature increase of only a 32 starts the boiling process at pumping temperature and pressure. This continuous flashing damages seal faces and compromises contacting seal life. With a non-contacting gas lubricated seal the liquid can turn to a gas in a controlled manner. Since there is no contact during operation, the temperature at the seal faces rises only a few degrees.
Violent flashing is eliminated.
The new generation of non-contacting gas lubricated seal has improved MTBM from as low as weeks to years. One fleet user reported 25 seal failures per year on liquid nitrogen when contacting seals were used. Similar savings have been developed for trucks handling argon and oxygen. John Crane Inc. He serves on the Editorial Advisory Board for Pumps and Systems.