Patent ID: 7739779

Claim:
A method for opening a cylindrical pressure vessel having an internal closure which includes a cover arranged for closure of the pressure vessel, the cover being arranged to assume two different closure positions in a longitudinal direction of the pressure vessel, a first closure position when the pressure vessel is pressurized, and a second closure position when the pressure vessel is essentially unpressurized, and a number of force-transmitting elements adapted to abut against a contact surface of the cover and a contact surface of an inner wall of the pressure vessel, which method comprises: relieving pressure from the pressure vessel; releasing said force-transmitting elements by moving the cover in the longitudinal direction of the pressure vessel, from the first closure position, where the cover is located when the pressure vessel is pressurized, to the second closure position; translating said force-transmitting elements away from said contact surface of the cover and said contact surface of the inner wall of the pressure vessel inwards toward a longitudinal center axis of the pressure vessel; and removing the cover and said force-transmitting elements.