Patent ID: 8172232

Claim:
A sealing apparatus, comprising: a stationary first machine component and a second machine component which is radially spaced from and rotatable relative to said first machine component about a longitudinal axis, a circumferential gap being formed by said radial space between said first and second machine components; at least one shoe having a first surface and a second surface spaced from said first surface, said at least one shoe being subjected to aerodynamic forces applied in a direction along said longitudinal axis, said first surface being formed with a sealing area circumferentially extending along one of said first and second machine components in a position to form a non-contact seal of said circumferential gap between them and at least one tooth element located upstream from said sealing area, a cavity being formed between said sealing area and said at least one tooth element, said at least one shoe being formed with a bleed hole connected to said cavity; a ring spaced from said at least one shoe along said longitudinal axis, said ring being mounted to the other of the first and second machine components, said ring circumferentially extending along said one of said first and second machine components; a number of circumferentially spaced spring elements each having opposed first and second ends, each of said spring elements extending longitudinally between said at least one shoe and said ring and being connected at said first end to said second surface of said at least one shoe and at said second end to said ring, said spring elements being effective to deflect and move with said at least one shoe in response to the application of aerodynamic forces to said at least one shoe in such a way as to assist in the creation of a primary seal of said circumferential gap between said first and second machine components.