Radar tank gauge for gas carriers
The Radar Tank Gauge is type approved, and due to its modular design, can be applied as primary and secondary level gauge onboard gas carriers.
- Approved for Custody Transfer (CTS)
- Continuous level verification - AutroCAL®
- Outstanding accuracy in the whole range
- Measuring range 0 to 50 metres
- Closed level gauge suitable for all tank designs
- Utilize 50 mm still pipe
- Modular design
- Intrinsically safe for use in all zones
Principle of operation
The Radar Tank Gauge employs the Frequency Modulated Continuous Wave (FMCW) principle with dual sweep technology to eliminate Doppler-effect caused by cargo movement. A frequency sweeping microwave signal is emitted by the radar through a still pipe. The distance (i.e. the ullage) is derived from the time delay of the reflected signal. The still pipe is assembled by sections of 6 meter lengths, where the top and bottom section lengths are adjusted to match the total tank height.
The pipes have ventilation holes allowing the vapour pressure inside and outside the pipe to stabilize, thus allowing the liquid to rise or fall unimpeded in the pipe.
Each pipe section is supplied with flanges prepared with reference markers. The liquid level and the markers are measured simultaneously, so the system automatically verifies itself at every measurement. By careful calibration of the pipe sections length before installation, the positions of the markers are recorded and stored in the system. By comparing the liquid echo with the signature plate echo, a continuous auto calibration of the measurement is done.
The electronic unit in the Radar Tank Gauge includes a patented signal detection method that ensures optimum performance. Combined with its superb signal-to-noise ration, GLA-310/5 offers the highest measurement reliability and accuracy. Each Tank Gauge is connected to a dedicated signal processing unit, where the AutroCAL® principle is employed.
AutroCAL® is a unique calibration and verification function in the KONGSBERG system. Gas vapour density and mixture of gases influence the propagation speed of the radar signal, thus the accuracy of the measurement.
By using pipe joint reference markers, AutroCAL® continuously compensates for the changes caused by the differences in the propagation speed.
AutroCAL® ensures high accuracy over the whole measurement range, independent of the gas mixture, pressure and temperature.
With AutroCAL®, the influence of the gas vapour density and composition is measured and compensated for automatically.