Mechanical seal

Claim 1

A ROTARY SEAL TO PREVENT LEAKAGE OF FLUID UNDER PRESSURE FROM BETWEEN RELATIVELY ROTATABLE PARTS COMPRISING A HOUSING, A ROTATABLE SHAFT WITHIN SAID HOUSING, A ROTATABLE SEAL MEMBER SURROUNDING SAID SHAFT ADAPTED TO ROTATE THEREWITH, A NON-ROTATABLE SEAL MEMBER BEING SUPPORTED BY SAID HOUSING IN A MANNER SUCH THAT RADIAL OUTWARD MOVEMENT AND ROTARY MOVEMENT OF SAID NON-ROTATABLE SEAL MEMBER WITH RESPECT TO SAID HOUSING IS RESTRICTED AND IN A MANNER SUCH THAT SAID NON-ROTATABLE SEAL MEMBER IS FREE SHIFT AXIALLY WITH RESPECT TO SAID HOUSING, SAID NON-ROTATABLE SEALING MEMBER HAVING A RADIALLY DISPOSED SEALING SURFACE AND A RADIALLY DISPOSED BACKUP SURFACE, SAID NON-ROTATABLE SEALING MEMBER BEING OF A MATERIAL MORE FLEXIBLE THAN SAID ROTATABLE SEALING MEMBER, SAID ROTATABLE SEALING MEMBER HAIVNG A RADIALLY DISPOSED SURFACE ADAPTED TO ENGAGE SAID RADIALLY DISPOSED SEALING SURFACE ON SAID NON-ROTATABLE SEALING MEMBER, MEANS FOR PREVENTING DISTORTION OF SAID NON-ROTATABLE SEALING MEMBER COMPRISING A BACKUP RING HAVING A SURFACE IN PRESSURE CO-PLANAR ENGAGEMENT WITH SAID RADIALLY DISPOSED BACK-UP SURFACE THROUGHOUT THE RADIAL EXTEND THEREOF, MEANS FOR INCREASING THE UNIT LOAD EXERTED BY SAID BACK-UP RING ON SAID NON-ROTATABLE SEALING MEMBER WHEREBY THE CO-PLANAR RELATIONSHIP BETWEEN THE BACK-UP RING AND THE NON-ROTATABLE SEALING MEMBER REMAINS SUBSTANTIALLY CONSTANT AND THE NON-ROTATABLE SEALING MEMBER IS SUPPORTED BY AN AREA SUBSTANTIALLY EQUAL TO THE AREA OF SAID BACK-UP SURFACE.