HYDRODYNAMIC BORE FINGER SEAL WITH SEALING PADS

摘要

The disclosed finger seals are designed to be operational under rotational velocity or a stationary condition. The contact surface of the finger seals is inclined in an axial direction. This incline causes a convergent leakage path between the finger foot surface and the bore. Therefore, the leakage flow passing through this gap exerts hydrodynamic lift on the finger and lifts the finger from the bore surface at design pressure. Since the slope is in the axial direction, the rotational velocity of the bore does not affect the hydrodynamic lift and the finger seals can operate at any rotational speed, unlike prior finger seal where the hydrodynamic lift is generated by rotational velocity. Each finger seal is pressure balanced. The pressure chambers on the two sides of each finger seal are connected through the finger cutouts. The finger seal design is such that the fingers lift and move away from the bore surface in radial direction. Therefore, the angle between the finger seal foot and the bore is constant at any lifted distance. In each seal stack up, in one form, each finger seal is designed with the specific required length to allow sufficient surface area for the hydrodynamic force such that the finger seals would be lifted from the bore surface at the design pressure.