Patent ID: 7855676

Claim:
A radar level gauge system, for determining a filling level of a product contained in a tank, said radar level gauge system comprising: a transceiver for generating, transmitting and receiving electromagnetic signals; an antenna arranged to direct transmitted electromagnetic signals towards a surface of the product contained in the tank, and to return reflected electromagnetic signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signals back to said transceiver; a hollow waveguide connecting said transceiver and said antenna for guiding said electromagnetic signals therebetween; a sealing member arranged to seal said waveguide to prevent fluid from passing into said waveguide from an interior of the tank; and processing circuitry connected to said transceiver and configured to determine said filling level based on said reflected electromagnetic signals, wherein: said radar level gauge system further comprises a leak indication member being movably arranged inside said hollow waveguide in such a way that a force resulting from leakage of said fluid at said sealing member causes a movement of said leak indication member when acting thereon; and said hollow waveguide is configured in such a way that said movement of the leak indication member causes a change in at least one microwave propagation characteristic of the hollow waveguide.