Gas filled envelope for a spark gap or the like

Claim 1

IN A GAS FILLED ENVELOPE FOR A SPARK GAP AND THE LIKE, IN COMBINATION, A FILLING TUBE GAS TIGHTLY CONNECTED TO SAID ENVELOPE AND COMMUNICATING AT ONE END THEREOF WITH THE INTERIOR OF SAID ENVELOPE, SAID TUBE HAVING A PORTION PROJECTING OUTWARDLY OF SAID ENVELOPE AND HAVING A FREE END; CLOSURE MEANS AT SAID FREE END OF SAID FILLING TUBE, SAID CLOSURE MEANS BEING MOVABLE BETWEEN A FIRST POSITION GAS TIGHTLY CLOSING SAID FREE END OF SAID TUBE AND A SECOND POSITION PERMITTING PASSAGE OF GAS THROUGH SAID TUBE; FITTING MEANS REMOVABLY AND GAS TIGHTLY FITTED OVER SAID PORTION OF SAID FILLING TUBE, SAID FITTING MEANS DEFINING AN ENCLOSED SPACE COMMUNICATING WITH THE INTERIOR OF SAID TUBE WHEN SAID CLOSURE MEANS IS IN SAID OPEN POSITION; OPERATING MEANS HAVING AN ENGAGING PORTION IN SAID ENCLOSED SPACE ADAPTED TO BE BROUGHT INTO ENGAGEMENT WITH SAID CLOSURE MEANS, AND AN OPERATING PORTION EXTENDING GAS TIGHTLY SEALED FROM SAID SPACE TO THE OUTSIDE OF SAID FITTING MEANS SO AS TO BE OPERABLE FOR MOVING SAID ENGAGING MEANS INTO ENGAGEMENT WITH SAID CLOSURE MEANS AND TO MOVE THE LATTER BETWEEN SAID POSITION THEREOF; PASSAGE MEANS COMMUNICATING AT ONE END THEREOF WITH SAID ENCLOSED SPACE AND ADAPTED TO BE CONNECTED AT THE OTHER END THEREOF TO APPARATUS FOR CAUSING FLOW OF GAS THROUGH SAID PASSAGE MEANS INTO AND OUT OF SAID SPACE; AND AT LEAST ONE SHUT-OFF VALVE IN SAID PASSAGE MEANS FOR OPENING AND CLOSING THE LATTER.