Patent ID: 7815224

Claim:
A fluid coupling device communicating with a rotor member and operable with either compressible or incompressible coolant media provided at a sealed pressure includes a housing having a cylindrical counterbore extending therethrough and a media inlet, a tubular carrier member having an outer surface positioned within the counterbore and axially moveable therein and communicating with the media inlet, including in combination: a primary seal assembly comprised of a rotating seal member mounted to the rotor member and a non-rotating seal member mounted to the carrier member; a secondary seal member positioned about the tubular carrier member and engageable with the housing to provide a seal therebetween; and wherein said primary seal assembly is structurally arranged to provide a predetermined gap between said rotating seal member and said non-rotating seal member when a compressible fluid coolant is directed through the media inlet and structurally arranged to provide that said rotating seal member engages said non-rotating seal member when an incompressible fluid coolant is directed through the media inlet, with said primary seal assembly having a balance ratio of between 0.5 and 0.67, wherein the balance ratio, B, is defined as a ratio according to the following equation: B = p f p where p f represents an average load imposed by the sealed pressure on a seal face of the primary seal assembly, and p represents the sealed pressure.