Abstract: A particulate exclusion mechanism for a gas lift off seal includes a band fixed to the stationary seal face and extending over the lift off region between the stationary and rotating seal faces, thereby forming an annular cavity surrounding the lift off region that traps barrier gas therein as it leaks through the lift off region and inhibits process fluid from entering the annular cavity and reaching the lift off region. The band can be made of a non-abrasive material such as PTFE or PEEK. The band can extend over the rotating seal face, and a portion of the band can be sufficiently flexible to allow the extended end of the band to constrict in diameter and contact the rotating seal face if the process pressure exceeds the barrier gas pressure. The extended end can include a thicker terminating portion that minimizes clearance with the rotating seal face.

Abstract: A particulate exclusion mechanism for a gas lift off seal includes a band fixed to the stationary seal face and extending over the lift off region between the stationary and rotating seal faces, thereby forming an annular cavity surrounding the lift off region that traps barrier gas therein as it leaks through the lift off region and inhibits process fluid from entering the annular cavity and reaching the lift off region. The band can be made of a non-abrasive material such as PTFE or PEEK. The band can extend over the rotating seal face, and a portion of the band can be sufficiently flexible to allow the extended end of the band to constrict in diameter and contact the rotating seal face if the process pressure exceeds the barrier gas pressure. The extended end can include a thicker terminating portion that minimizes clearance with the rotating seal face.

Abstract: A mechanical seal face has a significant increase in the ability of the seal to tolerate poor lubrication conditions such as dry running. The mechanical seal employs a thin, non-corrugated flat sheet of flexible thermally conductive graphite material placed between one of the mechanical seal faces and a metal surface such as a metal surface defined by a shaft sleeve or gland serving as a seal ring holder. The graphite sheet is located axially between a back face of the more thermally conductive mechanical seal ring and the metal face holder part. The conductive seal face material preferably is a ceramic or cermet material such as silicon carbide, tungsten carbide, silicon nitride, aluminum oxide, or a metallic material such as stainless steel.

Abstract: A mechanical seal face has a significant increase in the ability of the seal to tolerate poor lubrication conditions such as dry running. The mechanical seal employs a thin, non-corrugated flat sheet of flexible thermally conductive graphite material placed between one of the mechanical seal faces and a metal surface such as a metal surface defined by a shaft sleeve or gland serving as a seal ring holder. The graphite sheet is located axially between a back face of the more thermally conductive mechanical seal ring and the metal face holder part. The conductive seal face material preferably is a ceramic or cermet material such as silicon carbide, tungsten carbide, silicon nitride, aluminum oxide, or a metallic material such as stainless steel.