Dry Gas Seal System in centrifugal compressor

This video is about Dry Gas Seal System in Centrifugal Compressor

Before understanding dry gas sealing system , we should understand primary and secondary sealing arrangement.
So if you see sealing arrangement in compressor, you will find primary and secondary sealing stages are arranged in series.

First in board seal : The one on the compressor side is known as primary seal.

Out board seal: The one on the bearing side is known as secondary seal.
During normal operation the primary seal unit seal against full operating pressure. While secondary seal acts as a backup incase of inboard seal failure ( i.e. primary seal failure), secondary seal prevents gas leakage to atmosphere.

Barrier seal is provided between secondary seal and compressor bearings to prevent entry of lube oil into seal zone.