US Patent 9062775 Scooping hydrodynamic seal

A hydrodynamic face seal has a rotating first ring and a stationary second ring. The rotating first ring has an inner face. The stationary second ring has an inner face adjacent to the inner face of the rotating first ring. The inner face of the rotating first ring includes a groove having a fluid inlet portion and a hydrodynamic force generating portion. The fluid inlet portion of the groove has a depth greater than the hydrodynamic force generating portion of the groove. The fluid inlet portion has a minimum depth configured to create a higher pressure than a surrounding pressure around the rotating first ring, while not generating a hydrodynamic or hydrostatic force in the fluid inlet portion.