Underwater or underground oil storage - in upper part of tank foil-partitioned from lower part, water-filled to hold oil level constant

摘要

The tank is intended for storage or petroleum or similar liquids and is wholly or partly placed underwater or below ground level. It is subdivided into an upper and a lower compartment which are separated by flexible foil material and the upper compartment holds the oil whilst the lower compartment is filled with water. During discharge of oil, the lower compartment is filled with water, and vice versa, so that the liquid level in the tank remains approximately constant and external forces on the tank remain balanced by the contents.S Used for underwater or underground storage for petroleum etc. Balancing the external water or soil pressure on the tank by its contents enables the use of a relatively light tank structure and large diameter. The always present contents increase stability of the tank in high seas, hence reduced requirements for ballast and lighter tank roof structure. Pumping energy requirement is reduced. Greater fire safety and reduced pollution risk. Indication of any foil rupture in the water discharged from lower compartment so that action can be taken before pollution occurs.