Glass-to-metal tube coupling having indium seal means

Claim 1

A SELECTIVELY BREAKABLE VACUUM TIGHT GLASS-TO-METAL SEAL UNION COMPRISING A GLASS TUBE HAVING A FREE END AND A PREDETERMINED PORTION OF ITS PERIPHERAL SURFACE ADJACENT SAID FREE END COATED WITH A METAL SELECTED FROM THE GROUP OF INDUM AND INDIUM ALLOYS, A METAL TUBE HAVING AN END PORTION DEFINING A PROJECTING SHOULDER PORTION AND DEFINING A SEALING SURFACE FACING IN THE DIRECTION OF SAID GLASS TUBE AND EXTENDING AT RIGHT ANGLES TO SAID GLAS TUBE AND SAID METAL TUBE, A COMPRESSION RING MEMBER BEING SLIDABLY DISPOSED ON SAID GLASS TUBE AND HAVING A SUBSTANTIALLY FRUSTOCONICAL INNER SURFACE FACING IN THE DIRECTION OF SAID METAL TUBE END PORTION AND THE COATED GLASS TUBE END, A SUBSTANTIALLY ANNULAR GASKET MEMBER COMPRISING A METAL SELECTED FROM THE GROUP OF INDIUM AND INDIUM ALLOYS AND BEING INTERPOSED BETWEEN SAID METAL TUBE END PORTION AND SAID RING MEMBER SO AS TO ENCOMPASS SAID COATED GLASS TUBE END, A FIRST TIGHTENING MEMBER SLIDABLY MOVABLE ON SAID METAL TUBE INTO CONTACT WITH SAID PROJECTING SHOULDER PORTION AND SELECTIVELY MOVABLE AWAY FROM SAID SHOULDER PORTION, AND A SECOND TIGHTENING MEMBER SLIDABLY MOVABLE ON SAID GLASS TUBE AGAINST SAID RING MEMBER AND SELECTIVELY MOVABLE AWAY FROM SAID RING MEMBER, SAID FIRST AND SECOND TIGHTENING MEMBERS HAVING CORRESPONDING THREADED PORTIONS ADAPTED TO BE BROUGHT INTO TIGHTENING ENGAGEMENT WHEN SAID GLASS TUBE END IS PLACED ADJACENT TO SAID METAL TUBE END PORTION, AND TO BE SELECTIVELY UNTIGHTENED FROM EACH OTHER WHEN SAID SEAL UNION IS TO BE BROKEN.