Purge Seals The Dynamic (velocity) Seal is a simple device which ensures significant cost savings over time by reducing purge gas. The reverse conical baffle design reduces flow area in the flare tip while simultaneously increasing purge gas velocity. In combination with the Dynamic Seal, a constant flow of purge gas will maintain a seal in flare system, ensuring that air infiltration does not occur. A vortex effect is created as the exiting purge gas inspirates intruding air. This intruding air is drawn out of the boundary layer and into the exiting purge gas flow column, thus purging the flare tip. This technology is a standard on various flares.