Patent ID: 8037752

Claim:
Apparatus for measuring the filling level of a liquid having a surface in a container comprising: a first tube extending substantially parallel to a bottom of the container and having an opening in a direction towards the surface of the liquid; a second tube arranged at an angle to the first tube and fixedly connected thereto at the opening of the first tube, wherein the tubes form a tubular housing comprising two half-shell portions involving the respective longitudinal extent of the tubes, the two half-shell portions are fixedly connected together at longitudinally extending connecting surfaces, the tubular housing forms two parallel hollow spaces extending in the longitudinal extent of the housing, one of the hollow spaces serves substantially for conducting ultrasound and the other hollow space serves for guiding electric lines; a transmitting device arranged in the first tube in proximity to the container bottom for emitting ultrasound transmission pulses; a receiving device arranged in the first tube in proximity to the container bottom for receiving echo signals reflected at the surface of the liquid; an evaluation device for evaluating transit times of the ultrasound transmission pulses and echo signals; a reflector arranged in the first tube in proximity to the container bottom and in the region of the opening at given spacing relative to the transmitting and receiving devices for reflecting the ultrasound transmission pulses in the direction of the surface of the liquid and in the direction of the receiving device, whereby, the direction of the ultrasound transmission pulses emitted to the reflector and the direction of the echo signals reflected by the reflector extend substantially parallel to the container bottom; and a reference surface arranged in the proximity of the container bottom at a given spacing relative to the transmitting and receiving devices for reflecting the ultrasound transmission pulses in a direction in opposite relationship to the direction of incidence.