Method for determining properties of a medium and device for determining properties of a medium

A method for determining physical and/or chemical properties of a medium on the basis of at least one first and one second acoustic wave, which each have at least partly propagated through the medium from at least one transmitter to at least one receiver, wherein

• the acoustic waves each are generated by a transmit signal x0, x1,
• the first acoustic wave propagates through the medium along a first propagation direction and the second acoustic wave propagates through the medium along a second propagation direction identical to or different from the first propagation direction,
• for a received first acoustic wave a first receive signal y0r, y1r is generated after its propagation through the medium along the first propagation direction and for a received second acoustic wave a second receive signal y0s, y1s is generated after its propagation through the medium along the second propagation direction,
• an absolute runtime t0 of an acoustic wave from a transmitter to a receiver is determined from the receive signals y0r, y1r;
• y0s, y1s and by means of a determined absolute runtime t0 physical and/or chemical properties of the medium are determined,
• at least two different transmit signals x0, x1 of substantially the same fundamental frequency f are used, which have a specified phase offset to each other and with which a first and a second acoustic wave each is generated, so that for each propagation direction two receive signals y0r, y1r;
• y0s, y1s are generated, which originate from different transmit signals x0, x1, and
• an absolute runtime t0 of an acoustic wave between a transmitter and a receiver is determined by the four receive signals y0r, y1r;
• y0s, y1s.

A device for determining physical and/or chemical properties of a medium comprising

• an acoustic waveguide which includes an interior space to be filled with the medium,
• at least two transmitters which each are formed and provided for the generation of acoustic waves in the waveguide by a transmit signal x0, x1 of the transmitter, so that a generated acoustic wave propagates along the waveguide and at least partly through the medium,
• at least two receivers which are spatially spaced from each other along the waveguide and each are formed and provided for the generation of a first or second receive signal y0r, y1r;
• y0s, y1s for first or second acoustic waves reaching the respective receiver, wherein a first acoustic wave each propagates along a first propagation direction and for this purpose a first receive signal y0r, y1r is generated at a receiver and a second acoustic wave each propagates along a second propagation direction identical to or different from the first propagation direction and for this purpose a second receive signal y0s, y1s is generated at a receiver, and
• a signal processing device, by means of which from the receive signals y0r, y1r;
• y0s, y1s,
• when the second propagation direction is different from the first propagation direction, a runtime difference Δt between received first and second acoustic waves and/or,
• when the second propagation direction is different from or identical to the first propagation direction, an absolute runtime t0 of an acoustic wave from a transmitter to a receiver
• is determined, and which is formed and provided to determine physical and/or chemical properties of the medium with a determined runtime difference (Δt) and/or a determined absolute runtime t0.
• the transmitters of the device are formed and provided to each generate first and second acoustic waves with two different transmit signals x0, x1 of substantially the same fundamental frequency f and specified phase offset to each other, so that in the first propagation direction two distinguishable first and in the second propagation direction two distinguishable second receive signals y0r, y1r;
• y0s, y1s are generated by the receivers of the device, and
• the signal processing device is formed and provided to determine a runtime difference Δt and/or an absolute runtime t0 by the four receive signals y0r, y1r;
• y0s, y1s.