Oil balanced shaft seal

Claim 1

A BALANCED SEAL FOR A MEMBER THAT PASSES THROUGH AND IS MOVABLE IN THE HULL WALL OF A SHIP BELOW THE WATER LINE THEREOF, WHERE SEA WATER IS ON THE EXTERIOR SIDE OF SAID WALL, WHICH COMPRISES; SAID WALL HAVING AN APERTURED THERETHROUGH, A TUBULAR SLEEVE SECURED ENDWISE TO SAID WALL AT AND SURROUNDING SAID APERTURE, WITH ITS PASSAGE ALIGNED AND COMMUNICATING WITH SAID APERTURE, SAID MEMBER PASSING ENDWISE THROUGH SAID APERTURE AND SLEEVE AND HAVING BEARING IN SAID SLEEVE, SEPARATE ANNULAR SEALING RINGS CONFINED IN AND SPACED APART ALONG THE PASSAGE OF SAID SLEEVE AND BEING CUPSHAPED IN CROSS-SECTION, WITH THE CONCAVE SIDES OF THE CUP SHAPES FACING ONE ANOTHER, SEPARATE SPACER MEANS BETWEEN SAID RINGS FOR KEEPING THEM SEPARATED, AND MEANS INCLUDING A PUMP CONNECTED TO SAID SPACE BETWEEN SAID RINGS FOR CONTINUOUSLY SUPPLYING TO AND MAINTAINING IN SUCH SPACE BETWEEN SAID RINGS A LIQUID LUBRICANT UNDER A SELECTED PRESSURE SOMEWHAT ABOVE THE EXPECTED MAXIMUM PRESSURE OF THE SEA WATER ON SAID HULL WALL, AND PRESSURE ALARM MEANS IN FLUID COMMUNICATION WITH SEA WATER ON THE EXTERIOR SIDE OF THE HULL AND WITH THE SAID SPACE BETWEEN SAID RINGS, FOR SIGNALLING WHENEVER SUCH LUBRICANT PRESSURE BETWEEN SAID RINGS FAILS TO EXCEED THE SEA PRESSURE ON SAID HULL WALL BY A SELECTED MARGIN.