METHOD FOR DETECTING THE TILT OF A FLOATING ROOF FLOATING ON A MEDIUM STORED IN A TANK

The invention concerns a method for detecting the tilt of a floating roof (3) floating on a medium (4) stored in a tank (1), whereby a radar level gauge (5) is mounted in a fixed position on the tank (1), whereby the radar level gauge (5) is emitting signals in the direction of the floating roof (3) and receiving the echo signals reflected on the surface of the floating roof (3), comprising the steps of:a) determining and recording the level of the floating roof (3) during a period of time, whereby the period of time includes some filling/emptying cycles of the medium (4) in/from the tank (1),b) detecting and recording at least the echo amplitudes of the echo signals over the time during said period of time,c) filtering the echo amplitudes and recording the filtered echo amplitudes of the echo signals during said time period,d) calculating the gradient of the filtered echo amplitudes of the echo signals during said time period,e) calculating or providing a threshold value (T) for an tolerable deviation of the gradient of the echo amplitudes of the echo signals during said time period,e) generating an alert message that a roof tilting is detected if the deviation of the gradient of the echo amplitudes of the echo signals falls behind the threshold (T).