Mechanical seal containing a sealing face with grooved regions which generate hydrodynamic lift between the sealing faces

A mechanical face seal for providing a seal between a pair of relatively rotatable components comprising a first sealing ring adapted to be mounted non-rotatably and sealed with respect to one of said components, a second sealing ring adapted to be mounted non-rotatably and sealed with respect to the other component, said second sealing ring being mounted in axial alignment with the first sealing ring and means being provided to resiliently urge a sealing face of the second sealing ring axially into sealing engagement with a sealing face of the first sealing ring;

• the sealing face of one of the sealing rings having a first and a second set of hydrodynamic lift generating grooved areas, the grooved areas of each set being spaced angularly around the circumference of the sealing face the grooved areas of one set being spaced angularly of the grooved areas of the other set, the grooved areas of both sets opening to one edge of the sealing face and extending part way across the sealing face, each grooved area defining a trailing edge relative to the direction of rotation of one seal face relative to the other, the trailing edge being inclined in the plane of the sealing face at an obtuse angle to the direction of rotation each grooved area being of constant axial depth, the axial depth of the grooved areas of the first set being less than 10 .mu.m and the axial depth of the grooved areas of the second set being from 20 .mu.m to 125 .mu.m.