APPARATUS AND METHOD UTILISING BUOYANCY

摘要

A tower structure (2) for raising an object (6) introduced to the tower structure (2) at an operative lower end thereof to an operative upper end thereof by buoyancy of the object (6) in liquid contained in the tower structure. The object (6) exits from the tower structure at the operative upper end and is displaceable by the force of gravity acting on the object for returning the object 6 to a lower level for return to the tower structure via an entrance arrangement. The entrance arrangement includes an inlet chamber (53) for receiving the object and a ram (28) for transferring the object from the inlet chamber (53) into the tower structure 2. The ram (28) separates the inlet chamber (53) from a ram chamber (62) and liquid is added to equalise the pressure in the chambers (53, 62) with that in the tower structure prior to actuating the ram (28) to insert the object (6) in the tower structure.