SEALED, HEAT-INSULATED VESSEL HOUSED IN A BUOYANT STRUCTURE

摘要

The present invention relates to a buoyant structure comprising a sealed, heat-insulated vessel (1). An upper supporting wall (7) supports a turret (15, 21) for transferring cargo handling devices (16, 22). The turret comprises a sealed inner wall forming a sheath (22) inserted through the opening of the upper supporting wall (7) and sealably connected to the main sealing diaphragm (13) of the upper vessel wall around the entirety of the sheath. Primary and secondary exhaust devices allow release of gas exhaust from the respective primary and secondary spaces of the turret. A gas tank, containing a tracer gas that is non-condensable or has a condensation temperature lower than the low temperature of the liquefied gas contained in the vessel, is connected by means of a control valve to either the primary exhaust device or the secondary exhaust device. A gas detector capable of detecting the tracer gas is in communication with the other exhaust device.