Wellhead apparatus

Claim 1

IN A WELL HEAD CONSTRUCTION, THE COMBINATION OF A BODY MEMBER HAVING AN UPRIGHT PASSAGE THERETHROUGH; A SUPPORT MEMBER ADAPTED TO BE FIXED TO A STRING OF PIPE TO BE SUSPENDED FROM THE WELL HEAD, SAID SUPPORT MEMBER BEING DIMENSIONED FOR DOWNWARD INSERTION INTO SAID PASSAGE, SAID BODY MEMBER AND SAID SUPPORT MEMBER HAVING COOPERATING SHOULDER MEANS ENGAGED TO SUPPORT SAID SUPPORT MEMBER ON SAID BODY MEMBER WHEN SAID SUPPORT MEMBER HASA BEEN INSERTED INTO SAID PASSAGE. SAID SUPPORT MEMBER HAVING A BODY PORTION SUBSTANTIALLY COMPLETELY FILLING SAID PASSAGE WHEN SAID SUPPORT MEMBER IS DISPOSED WITH SAID SHOULDER MEANS IN ENGAGEMENT, AND AN UPPER PORTION OF REDUCED TRANSVERSE CROSS SECTION DISPOSED ABOVE SAID BODY PORTION, THERE BEING AN UPPER ANNULAR SPACE, SURROUNDING SAID UPPER PORTION OF SAID BODY MEMBER, AND A LOWER ANNULAR SPACE SURROUNDING THE SUSPENDED PIPE, WHEN SAID SUPPORT MEMBER IS INSTALLED IN SAID BODY MEMBER, SAID SUPPORT MEMBER HAVING FLOW DUCT MEANS EXTENDING UPWARDLY THERETHROUGH TO COMMUNICATE, WHEN OPEN, BETWEEN SAID UPPER AND LOWERANNULAR SPACE; MOVABLE VALVE MEANS CARRIED BY SAID SUPPORT MEMBER FOR MOVEMENT BETWEEN A FIRST POSITION, IN WHICH IT OPENS SAID FLOW DUCT MEANS AND A SECOND POSITION, IN WHICH IS CLOSES SAID FLOW DUCT MEANS; AND YIELDABLE MEANS BIASING SAID MOVABLE VALVE MEANS TO SAID SECOND POSITION, SAID MOVABLE VALVE MEANS BEING SO CONSTRUCTED AND ARRANGED AS TO PRESENT AN UPWARDLY FACING ELEMENT FOR ENGAGEMENT FROM ABOVE SAID SUPPORT MEMBER TO ACTUATE SAID MOVABLE VALVE MEANS TO SAID FIRST POSITION.