Self aligning spiral groove face seal

In a self aligning spiral groove gas seal having a stationary sealing ring and a primary sealing ring with opposed radially extending faces, one of said rings being sealingly affixed to a housing and the other affixed to the shaft, the improvement comprising:

• spiral grooves extending inwardly from one circumference of the face of one of said rings, said grooves having a depth of between approximately 0.0001 and 0.0003 inches, said grooves extending across the face of said ring to provide a dam width ratio of between approximately 0.5 and 0.8 according to one of the following formula ##EQU6## where groove diameter is the diameter of a circle defined by the boundary of the grooved area and the ungrooved area in said face, ID is the internal diameter and OD is the outside diameter;
• and
• said seal having a balance of between 0.8 and 0.9 according to the formula ##EQU7## where OD is the outside diameter of the sealing interface, ID is the inside diameter and BD is the balance diameter.