Dry gas seals are a crucial part of today’s centrifugal compressors. With dry gas seals, machined-in lift profiles on one side of the seal face direct gas inward toward an extremely flat portion of the face. The gas flowing across the face generates a pressure that maintains a minute gap between the faces, optimizing gas film stiffness and providing the highest possible degree of protection against face contact. The seal’s film stiffness compensates for varying operations by adjusting the gap and pressure to maintain stability.
While dry gas seals are an effective, reliable and robust standard sealing solution for centrifugal compressors in all kinds of industry processes, they require a continuous supply of clean gas to ensure the seal faces are lifting off at optimal levels for the best possible gas leakage performance. Both pressurized and unpressurized dry gas seals utilize clean “seal gas” upstream of the dry gas seal to establish a barrier against the potentially contaminated process stream. Pressurized dry gas seals may use a different clean source to energize the seal faces, but a seal gas supply still acts upstream to protect against process contamination.