Abstract: A method for determining a liquid level with the aid of ultrasonic pulses improves the measuring accuracy of the liquid level in a container with an echo time measurement of ultrasonic pulses and a mean sound velocity. The mean sound velocity is extrapolated from at least two reference sound velocities in the liquid. In this way it is possible to achieve a measuring accuracy of less than a millimeter, independently of the liquid level. A device for carrying out the method has a main measuring path, at least one device for transmitting and receiving ultrasonic pulses, at least two reference paths for determining sound velocities, and a computer unit. The computer unit extrapolates from the sound velocities to the mean sound velocity.

Abstract: A rod shaped or tubular housing for a sensor includes an interior space provided with upper and lower compensating openings and within which an ultrasound measured distance device. Below the ultrasound measured distance device, the interior is connected to the lower compensating opening through a narrow channel proceeding in an axial direction of the housing. The housing is formed of two half shells of plastic joined to one another whose wall parts engage into one another to form the narrow channel. The ultrasound transducers and the electrical leads are embedded into the half shells. A second ultrasound measured distance device which is in direct communication with the surrounding space may be provided above the interior space. The ultrasound transducer of the measured distance device is excited to transmit in a pulsed fashion.