Patent attributes
A mechanical seal designed for gas applications minimizes leakage even when the pressure differential changes direction, such as during rapid deceleration of a turbocharger. The seal faces include both inner (ID) and outer (OD) diameter recessed features configured to admit gas between the faces from the inner and outer face diameters respectively. In embodiments, the ID features hydro-dynamically provide a pressurized gas cushion between the seal faces under normal conditions, and the OD features provide a cushion when the pressure differential is reversed. According to the embodiment, the ID and OD features can be provided in only one seal face, or distributed among both seal faces. For example, one seal face can include the ID features and the other the OD features. The ratio of the area covered by the ID and OD features, divided by the total seal face area, can be at least 0.75 or greater.
