Low and reverse pressure application hydrodynamic pressurizing seals
The present invention relates to circumferential seal ring segments positioned around a rotating shaft so as to prevent fluids from leaking from a lubricant sump during both low and high pressure conditions. The circumferential seal is comprised of a plurality of adjoining annular ring segments facing the rotating shaft. Each sealing ring segment includes a dead end circumferential groove on a shaft-side face of each sealing ring such that, when the segments are joined, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation. At least one additional groove is contained on the shaft-side face of each sealing ring segment. The additional groove(s) directs and creates pressurized air within the dead end circumferential groove, either directly or indirectly maintaining a seal between the ring segments and the shaft. A bleed hole may also be provided to create a seal between each sealing segment.
1. A seal assembly for sealing a liquid region from a gas region across an annular surface of a rotating shaft comprising:
a plurality of adjoining annularly sealing ring segments facing the rotating shaft wherein each sealing ring segment includes a dead end circumferential groove machined within a shaft-side face of each sealing ring segment such that, when the sealing ring segments are joined about the annular surface, the dead end circumferential groove of each sealing ring segment extends arcuately in direction of shaft rotation; and
a plurality of additional grooves extending across the shaft-side face of each sealing ring segment leading to the dead end circumferential groove wherein the additional grooves are in fluid communication with the dead end circumferential groove and direct a fluid into the dead end circumferential groove;
each additional groove is a hydrodynamic inclined pumping groove oriented at an oblique pitch angle relative to a longitudinal axis of the sealing ring segment and in concert with direction of rotation of the rotating shaft so as to direct fluid flow generated from the rotating shaft into the dead end circumferential groove;
the sealing ring segment includes more than one hydrodynamic inclined pumping groove wherein each hydrodynamic inclined pumping groove has a unique depth.