Multiple land seal

Claim 1

A LOW TEMPERATURE SEAL FOR PREVENTING FLOW OF PRESSURIZED FLUID BETWEEN TWO CO-AXIAL CYLINDRICAL SURFACES COMPRISING THE COMBINATION OF A SEAL MEMBER HAVING A FLEXIBLE, RADIALLY EXTENDING ANNULAR BASE, AND AN OUTER AND AN INNER RESILIENT FLANGE AXIALLY EXTENDING FROM SAID BASE SUBSTANTIALLY PARALLEL TO ONE ANOTHER, EACH OF SAID FLANGES BEING PROVIDED WITH A PLURALITY OF CONTINUOUS LANDS AND GROOVES UPON ITS EXTERNAL PERIPHERY, SAID LANDS ON ONE OF SAID FLANGES BEING DIRECTED GENERALLY AWAY FROM THOSE UPON THE OTHER OF SAID FLANGES AND EXTENDING OVER THE ENTIRE EFFECTIVE LENGTH OF SAID EXTERNAL PERIPHERIES, SAID SEAL BEING AXIALLY RETAINED IN AN INTERFERENCE FIT BETWEEN SAID CYLINDRICAL SURFACES, EACH OF SAID LANDS BEING IN SEALING CONTACT WITH ONE OF SAID CYLINDRICAL SURFACES, EACH OF SAID GROOVES FORMING A FLUID TRAP WITH ONE OF SAID SURFACES, AND AN ANNULAR RING CONSTRUCTED FROM A MATERIAL HAVING A LOWER COEFFICIENT OF EXPANSION THAN SAID CYLINDRICAL SURFACES AND SAID SEAL MEMBER, SAID RING BEING LOCATED RADIALLY INWARD OF AND IN CONTACT WITH THE OUTER OF SAID FLANGES AND EXTENDING FROM THE FREE END OF SAID OUTER FLANGE TO THE POINT OF ATTACHMENT OF SAID OUTER FLANGE TO SAID BASE, SAID RING RETAINING SAID LANDS UPON SAID OUTER FLANGE IN SEALING CONTACT WITH THE OUTER OF SAID CYLINDRICAL SURFACES THROUGHOUT LOW TEMPERATURE OPERATIONAL PHASES.