Gauging systems

- Electro-pneumatic system – This system involves blowing air down the pipe to the liquid in the tank and measuring the pressure needed to force the liquid out of the pipe .

- Hydrostatic pressure system – The gauge sensor indicates the level by measuring the pressure of the contents of the tank .

- Radar tank gauging system – A radar transmitter is installed in each cargo tank at the upper deck level. The length of time taken for the radar wave to return to the radar transmitter from the surface of the cargo is fed into a computer located within the superstructure, which determines the contents of the tank.

- TankRadar system – Radar-based monitoring system developed by Saab Marine Electronics. A radar gauge is installed outside the tank, thus making maintenance and repair a much simpler task. The electronic box and temperature and vapour pressure sensors can easily be removed, tested or replaced by simply closing the ball valve. In 1998 the first Saab radar gauge was tested onboard an LNG carrier with success. TankRadar sends microwaves through a smooth strength cone from an electronic box where the microwaves are generated into a still pipe that stretches from top to bottom of the LNG tank. The pipe, which is penetrated with ventilation holes to equalise the level in the pipe, enables the microwaves to measure the liquid level accurately.

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