Face seal with angled grooves and shallow annular groove

A fluid seal device cooperating between a housing and a rotatable shaft for creating a fluid seal between high and low pressure regions, said device comprising:

• a first seal ring mounted on the shaft for rotation therewith and a second seal ring disposed adjacent the first seal ring and being non-rotatably mounted relative to the housing;
• said first and second seal rings respectively defining thereon opposed first and second flat annular seal faces adapted to substantially axially abut to define an annular seal interface which extends radially between and is defined by radially spaced first and second diameters which respectively communicate with said high and low pressure regions, one of said seal rings being axially movable and normally urged axially toward the other seal ring;
• a groove pattern formed in one of said seal faces and in communication with the high pressure region for causing a thin film of pressurized fluid to be interposed between said seal faces to create a small clearance therebetween;
• said groove pattern including first groove means formed in said one seal face for creating a hydrodynamic fluid seal between the opposed seal faces when the first and second seal rings relatively rotate;
• said groove pattern including second groove means formed in said one seal face for creating a hydrostatic fluid seal between said opposed seal faces when said first and second seal rings are stationary relative to one another;
• said first groove means including a plurality of first grooves disposed in generally uniformly angularly spaced relationship around said one seal face, said first grooves being angled so as to project circumferentially and radially from said high pressure diameter toward said low pressure diameter;
• said second groove means including an annular groove formed in said one seal face in radially spaced relation between said first grooves and said low pressure diameter, said annular groove communicating with inner ends of said plurality of first grooves;
• said first grooves having an average longitudinally-extending depth which is greater than the depth of said annular groove, and the inner ends of said first grooves defining abrupt damlike walls;
• a plurality of communication passages disposed in angularly spaced relationship around said one seal face with each said communication passage extending radially so as to have one end thereof in communication with said annular groove and an opposite end thereof in communication with a respective one of said first grooves, each said communication passage having a transverse width as defined circumferentially in said one seal face which is a small fraction of the transverse width of said first groove as defined in said one seal face so that said communication passages function primarily to supply fluid from said first grooves to said annular groove;
• and
• said one seal face defining thereon an annular non-grooved flat land extending radially between said low pressure diameter and said annular groove diameter.