| 摘要 |
This invention discloses a completely different hydrodynamic gas seal configuration from both the Rayleigh bearing and other prior art. Instead of the shallow, wide, and short single pocket geometry for the Rayleigh bearing, and instead of the multiple depth grooves of the other prior art teachings, the hydrodynamic seal in this invention has a sealing face with lift pockets therein that are deep (normally in the range of about 0.010 inches to about 0.025 inches deep), narrow, long, multiple, coextensive, parallel, and single-depth. This invention incorporates the same basic hydraulic principle of generating pressure rise by the shearing gradient between the rotating shaft and stationary carbon elements, and therefore produces a force which is opposite in direction to the rubbing force generated by the ambient pressure drop across the seal. In this invention the forces are more evenly balanced across the axial face of the seal ring segments, thereby accommodating any conicity of the shaft race. Seals of both the circumferential type and the face type are provided. Furthermore, the lift pockets are of a depth sufficient that, in the event of wear of the sealing face, an increase in pressure in the lift pockets occurs as a consequence of the reduction in depth to move the seal member away from the rotating shaft, thereby causing the seal gap to be self-regulating in size.
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