Patent ID: 9638326
Date: 2017-05-02
CPC Classifications: F16J

Claim:
1. A ring seal assembly comprising: a shaft having an outer circumferential surface with a diameter; a plurality of arc-shaped ring segments mounted around the outer circumference shaft and forming a ring seal with an innermost diameter, each of the plurality of ring segments having a radially outer face, a radially inner face, a first axial side face, a second axial side face, a first circumferential end and a second circumferential end, the plurality of ring segments being shiftable between an arch-bound configuration wherein the first circumferential end of each ring segment circumferentially contacts the second circumferential end of an other ring segment of the plurality and a non-arch-bound configuration wherein the first circumferential end of each ring segment is circumferentially spaced from the second circumferential end an other ring segment of the plurality, and that the innermost diameter of the ring seal is greater in the non-arch-bound configuration than in the arch-bound configuration; a spring biasing the plurality of arc-shaped ring segments toward the arch-bound configuration; and at least one circumferential ramp in the radially inner face of each of the plurality of ring segments configured to generate an air cushion when the shaft rotates inside the ring seal to radially expand the innermost diameter of the ring seal by transitioning the plurality of ring segments from the arch-bound configuration to the non-arch-bound configuration, wherein the ring segments are sized such that the radially inner faces of the ring segments are radially spaced from the outer circumferential surface of the shaft by a gap while in the arch-bound configuration so that the ring seal is not in contact with the shaft under low rotational speed and shaft startup conditions.