A method of installing a valve-bearing assembly on an underwater oil well head and for checking the sealing-tightness of the pipes connected thereto, in a single operation without the use of a diver, comprises coupling the assembly to a tool connected to riser of a surface support and which includes...http://www.google.de/patents/US4046192?utm_source=gb-gplus-sharePatent US4046192 - Method and apparatus for installing a control valve assembly on an underwater well head
