Leakage inspection apparatus for liquid storage tank technical field

A leakage inspection apparatus for a liquid storage tank, wherein at least a part of a periphery of the liquid storage tank is submerged in water, the apparatus comprising:

• a depressurizing device that depressurizes an inside of the liquid storage tank;
• a rod part adapted to be inserted in the liquid storage tank;
• a float that is fitted to the rod part to float on a surface of liquid in the liquid storage tank, the float being movable along the rod part in accordance with displacement of the liquid surface;
• a moving magnet provided in the float;
• a reference magnet fixed to a lower part of the rod part to be situated in the liquid in the liquid storage tank;
• a magnetostrictive linear sensor that detects a position of each of the moving magnet and the reference magnet;
• a measuring device which determines a position of the moving magnet relative to the reference magnet in accordance with a signal from the displacement sensor, and which determines whether or not displacement of the moving magnet relative to the reference magnet is equal to or more than a predetermined amount;
• an acceleration sensor which is attached to a fixed object continuing to the liquid in the liquid storage tank and which detects acceleration of a vibration;
• and
• a determining device that determine whether or not a change in a signal from the acceleration sensor is equal to or more than a predetermined amount.