Explosion proof radar level gauge

A radar level gauge for determining the filling level of product in a tank, said gauge comprising:

• a housing with a housing wall enclosing a compartment providing explosion proof protection;
• RLG circuitry located inside compartment, said circuitry in use having an available electrical and/or thermal energy incompatible with intrinsic safety requirements;
• a signal propagation device located outside said compartment, said signal propagation device being adapted to direct a microwave transmit signal toward said product and return reflections thereof from a surface of said product;
• an explosion proof first signal passage in said housing wall, said first signal passage providing a transmission line for said microwave transmit signal between said RLG circuitry and said signal propagation device;
• an explosion proof second signal passage in said housing wall, said second signal passage providing a two-wire interface for electrically conductively connecting said radar level gauge to an intrinsically safe system located externally of said radar level gauge, to provide at least one of:
• communication between said radar level gauge and said intrinsically safe system, and power supply to said RLG circuitry;
• and
• an electrical barrier connected between said RLG circuitry and the two-wire interface, said electrical barrier preventing energy or voltages in said RLG circuitry from compromising the intrinsic safety of an intrinsically safe system connected to the two-wire interface.