Vacuum jacketed pipe line and joint construction therefor

Claim 1

A THERMALLY INSULATED PIPE LINE STRUCTURE FOR TRANSPORTING A STREAM OF HIGH PRESSURE FLUID COMPRISING: AN INNER PIPE MEMBER SUSPENDED WITHIN AN OUTER PIPE MEMBER OF LESSER BRUSTING STRENGTH THAN SAID INNER PIPE MEMBER AND DEFINING THEREWITH AN ANNULAR SPACE WHICH WHEN EVACUATED REDUCES HEAT TRANSFER BETWEEN THE PIPE MEMBERS; TWO AXIALLY SPACED-APART SEALING MEANS EXTENDING ACROSS SAID ANNULAR SPACE AND DIVIDING SAID ANNULAR SPACE INTO TWO ELONGATED ANNULAR SECTIONS AND A THIRD ANNULAR SECTION, SAID THIRD ANNULAR SECTION BEING DISPOSED BETWEEN SAID SEALING MEANS AND BEING OF SMALL AXIAL LENGTH RELATIVE TO SAID ELONGATED SECTION, EACH OF SAID SEALING MEANS INCLUDING MEANS RESPONSIVE TO A PREDETERMINED HIGH FLUID PRESSURE IN THE RESPECTIVE ELONGATED ANNULAR SECTION FOR PASSING FLUID FROM THAT SECTION INTO SAID THIRD ANNULAR SECTION AND FOR PREVENTING PASSAGE OF HIGH PRESSURE FLUID FROM SAID THIRD ANNULAR SECTION INTO EITHER OF SAID ELONGATED ANNULAR SECTIONS; AND PRESSURE RESPONSIVE MEANS ASSOCATED WITH SAID THIRD ANNULAR SECTION FOR AUTOMATI-