Method and device for determining a liquid level with the aid of ultrasonic pulses

In a device for determining a liquid level in a container from an echo time measurement, the improvement comprising:

• a main measuring path and at least two reference paths;
• at least one transducer device located at one end of said main measuring path and at one end of said at least two reference paths for transmitting and receiving ultrasonic pulses;
• said at least two reference paths having at least one reflector device located in the liquid for determining respective reference sound velocities between said at least one transducer device and said at least one reflector device located in the liquid along said at least two reference paths;
• and
• a computer unit for determining a characteristic of a mean sound velocity in the vertical direction up to a liquid level by extrapolation from the reference sound velocities of said at least two reference paths, said computer unit determining the liquid level from the echo time of the ultrasonic pulses reflected at a liquid surface and the mean sound velocity in the vertical direction up to said liquid level.