Acoustic liquid measurement

A method for providing a temperature compensated measurement of the level of a liquid in a tank, comprising:

• transmitting an acoustic signal from a transducer into a waveguide adapted to extend into the liquid,
• receiving a reflected acoustic signal to the transducer from the waveguide, and directing a flow of heat transfer fluid originating from a heat transfer system along the exterior of a portion of the waveguide which during operation is located above the liquid level.

A device for controlling a heat regulating device adapted to regulate a temperature of a liquid in a tank, comprising:

• a transducer for transmitting and receiving acoustic signals,
• a waveguide connected to the transducer, said waveguide having a reference portion adapted to be located above the liquid surface when said device is arranged in said tank,
• and a control device configured to measure the speed of sound in said reference portion as an indication of a temperature in the liquid, and control the heat regulating device based on the indicated temperature.

A method for controlling a heat regulating device adapted to regulate a temperature of a liquid in a tank, said method comprising the steps of:

• transmitting an acoustic signal from a transducer into a waveguide, receiving a reflected acoustic signal to the transducer from the waveguide,
• measuring the speed of sound in a reference portion of the waveguide located above the liquid surface, as an indication of a temperature in the liquid;
• controlling the heat regulating device based on the indicated temperature.